Text Book Solutions All Class

01. Chapter Notes: Number System

February 17, 2026 by khushikhanera

Introduction

Number system is a writing system used for expressing numbers. A number is a mathematical object used to count, label and measure.

Types of Numbers

Natural numbers: All counting numbers are called natural numbers. It is denoted by “N”.

Example: N = {1, 2, 3, 4 … .}

Natural numbers are represented on the number line as follows:

Whole numbers: The group of natural numbers including zero is called whole numbers. It is denoted by “W”. Zero is a very powerful number because if we multiply any number with zero it becomes zero. All natural numbers along with zero are called whole numbers.

Example: W = {0, 1, 2, 3, 4 … .}

Whole numbers are represented on number line as follows:

Integers: The collection of all whole numbers and negatives of all natural numbers or counting numbers are called integers. They are denoted by “Z” or “I”. All whole numbers are integers, but all integers are not whole numbers

Example: Z or I = {… − 3, −2, −1, 0, 1, 2, 3 … . .}

Integers represented on number line as follow:

Real numbers

The collection of rational & irrational numbers together forms real numbers. The set of real numbers is denoted by symbol R. How do you know whether any number is real number or not?
If that number can be shown on number line then that number is a real number. So, any number which can be shown on the number line is real number.

Example: √2 , √3, −5, 0 , 1/5 5 etc…. All rational numbers are real numbers but all the real numbers are not rational numbers. Also, all irrational numbers are real numbers, but the reverse is not true

Rational numbers: Numbers that can be represented in the form of p/q where p & q are integers & q ≠ 0 are called rational numbers. The word rational came from the word ‘ratio’. It is denoted by letter Q and Q is taken from the word quotient. All integers are rational numbers.

Example: Q ={1/2, 3, -4, 3/2 etc ….}

Rational numbers also include natural numbers, whole numbers and integers. This can be explained using following example:

Example: –16 can also be written as -16/1 Here p = – 16 and q = 1. Therefore, the rational numbers also include the natural numbers, whole numbers and integers.

Equivalent rational numbers: The equivalent rational numbers are numbers that have same value but are represented differently.

Example: If a/b is equivalent to c/d and a/b = x then c/d = x

Also, if a/b = c/d, then a x d = b x c.

Irrational numbers: A number which can’t be expressed in the form of p/q and its decimal representation is non-terminating and non-repeating is known as irrational numbers. It is denoted by “S”.

Example: S = √2 = 1.4142135… . , √3 = 1.73205 … . , etc

Methods to determine rational number between two numbers

We know that there are infinitely many rational numbers between any given rational numbers. Hence, for determining one or more than one rational number between two given rational numbers we use the following methods

(i) When one rational number is to be determined:
Let a and b be two rational numbers, such that b > a. Then, Methods to determine rational number between two numbers is a rational number lying between a and b

Example: Find a rational number between 4 and 5 Here, 5 > 4

We know that, if a and b are two rational numbers, such that b > a. Then, Methods to determine rational number between two numbers is a rational number lying between a and b.
So, a rational number between 4 and 5 =

(ii) When more than one rational number are to be determined:
Let a and b be two rational numbers, such that b > a and we want to find n rational numbers between a and b. Then, n rational numbers lying between a and b are
(a + b), (a + 2d ), (a + 3d), ……….(a + nd), where, d = ( b -a ) / (n + 1)
Here, a and b are two rational numbers n is the number of rational numbers between a and b

Example (i): Find six rational numbers between 3 and 4

Here, 4 > 3
So, let a = 3 and b = 4 and n = 6
Since, d = b -a / n + 1

Now,

Hence, the required six rational numbers lying between 3 and 4 are

Example (ii): Find four rational numbers between − 6 and– 7.

Here, −6 > −7
Let a = − 7, b = − 6 and n = 4
Now, d = b -a / n + 1
=
So, four rational numbers between – 6 and − 7 are (a + d), (a + 2d), (a + 3d) and (a + 4d)
i.e.,  and
=  and
=  and
The above rational numbers are the rational numbers which lie between – 6 and – 7.

Try yourself:Which of the following is an example of a rational number?

A.π
B.√2
C. 3/4
D.e

Irrational number

A number which can’t be expressed in the form of p/q and its decimal representation is non-terminating and non-repeating is known as irrational numbers. The set of irrational numbers is denoted by “S”.

Example: S = √2 ,√3 , π, etc. ..

Locate an irrational number on the number line:
We see how to locate an irrational number on number line with the help of following example:

Example: Locate √17 on the number line

Here, 17 = 16 + 1 = (4)² + (1)²(Sum of squares of two natural numbers)
So, we take a = 4 and b = 1
Now, draw OA = 4 units on the number line and then draw AB = 1 join OB.

By using Pythagoras theorem, in ∆OAB
Irrational number
Taking O as the centre and radius equal to OB, draw an arc, which cuts the number line at C. Hence, OC represents √17.

Real Numbers and their Decimal Expansion

Real numbers: The collections of rational & irrational numbers together form real numbers. They are denoted by R. Every point on the number line is a real number.

Rational and Irrational numbers are Subsets of Real Numbers

Example: √2, √3, −5, 0, 1/5, 5 etc…. All rational numbers are real number but all real numbers are not rational numbers. Also, all irrational numbers are real number, but the reverse case is not true.

Real numbers and their decimal expansion: The decimal expansion of real numbers can be either terminating or non – terminating, repeating or non – terminating non – repeating. With the help of decimal expansion of real numbers, we can check whether it is rational or irrational.
(i) Decimal expansion of rational numbers:
Rational numbers are present in the form of p/q, where q ≠ 0, on dividing p by q, two main cases occur,
(a) Either the remainder becomes zero after few steps
(b) The remainder never becomes zero and gets repeating numbers.

Case I: Remainder becomes zero
On dividing p by q, if remainder becomes zero after few steps, and then the decimal expansion terminates or ends after few steps. Such decimal expansion is called terminating decimal expansion.

Example: Real Numbers and their Decimal Expansion

On dividing   we get exact value 0.625 and remainder is zero.
So, we say that  is a terminating decimal expansion.
On dividing  we get exact value 0.625 and remainder is zero. So, we say that    is a terminating decimal expansion.

Case II: Remainder never becomes zero
On diving p by q, if remainder never becomes zero and the sets of digits repeats periodically or in the same interval, then the decimal expansion is called non – terminating repeating decimal expansion. It is also called non – terminating recurring decimal expansion.
Example (i):

= 0.333… . . or = 0. 3= [The block of repeated digits is denoted by bar ‘– ‘over it]
On dividing we get the repeated number 3 and remainder never becomes zero. Hence, 1 by 3 has a non – terminating repeating decimal expansion.

Example (ii): Real Numbers and their Decimal Expansion

Hence, = 0.On dividing 4 by 13 we get the repeated numbers 0.30769230 again and again, and remainder never becomes zero. Hence, 4 by 13 has a non – terminating repeating decimal expansion.

Methods to Convert Non – Terminating Repeating Decimal Expansion in the form of p by q

Suppose the number is in the form of Methods to Convert Non – Terminating Repeating Decimal Expansion in the form of p by q ( and we have to convert the given number in the form of p by q. Follow the following steps:
Step I: Firstly, transform the non – repeated digits between decimal point and repeating number to left side of decimal by multiplying both sides by 10ⁿ
Where n = number of digits between decimal points and repeating numbers. i.e., Methods to Convert Non – Terminating Repeating Decimal Expansion in the form of p by q . (In the above expression we see that one digit “b” exist between decimal point and repeating number. Hence,we multiply both side by 10¹. We get,
Step II: Count the number of digits in repeating number and then multiply equation (1) by that power of 10 and the equation becomes

Methods to Convert Non – Terminating Repeating Decimal Expansion in the form of p by q Step III: Subtract equation (1) from equation (2) we get,

Methods to Convert Non – Terminating Repeating Decimal Expansion in the form of p by q Example (i): Express in the form of p by q

Assume the given decimal expansion as x
Let,
x =
x = 0.666 … … . . (i)
Here, only 1 digit is repeating. Hence, multiplying both side of equation (i) by 10 we get,
10x = 6.66… … … (ii)
Subtracting equation (i) from (ii) we get,
10x – x = 6.66 – 0.66
9x = 6.66 – 0.66
9x = 6
x = 6/9 = 2/3
Hence,

Example (ii): Express 0.4 in the form, where p and q are integers and q ≠ 0

Let, x = 0.43535 ……(i)
Here, we see that one digit exit between decimal point and recurring number
So, we multiply both sides of equation (i) by 10, we get
10x = 4.3535 …… (ii)
Here we see that two digits are repeated in the recurring number
So, we multiply equation (ii) by 100, we get
1000x = 435.3535 …… (iii)
Subtracting equation (ii) from equation (iii), we get
1000x − 10x = 435.3535 − 4.3535
990x = 431
x =
Hence,

Example (iii): Express 0.00232323…. in the form, where p and q are integers and q ≠ 0

Let, x = 0.00232323 = 0.00 ……(i)
Here, we see that two digits exist between decimal point and recurring number
So, we multiply both sides of equation (i) by 100,
100x = 0.232323…… (ii)
Here we see that two digits are repeated in the recurring number
So, we multiply equation (ii) by 100, we get
10000x = 23.2323 …… (iii)
Subtracting equation (ii) from equation (iii), we get
10000x − 100x = 23.2323 − 0.232329
990x = 23
x =
Hence, 0.002323 =

Also read: HOTS Questions: Number System

Decimal Expansion of Irrational Numbers

The decimal expansion of an irrational numbers is non-terminating non-recurring or a number whose decimal expansion is non – terminating and non-recurring is called irrational.
Example: √3 and π are the examples of irrational numbers because, the values of √3 = 1.7320508075688772…. and π = 3.14592653589793 are non-terminating non-recurring.

Example (i): Find the irrational number between and

∴
Now,
Thus,
It means that the required rational numbers will lie between and . Also, we know that the irrational numbers have non-terminating non-recurring decimals. Hence, one irrational number between and is 0.20101001000… . .

Example (ii): Find the two irrational numbers between and

If  = 0.333 (Given)
We have,  = 0.333 (Given)
Hence,  = 2 ×  = 2 × 0.333 = 0.666
So, the two rational numbers between   and   may be 0.357643… and 0.43216 (In this solution we can write infinite number of such irrational numbers)

Example (iii): Find two irrational numbers between √2 and √3 .

We know that, the value of
√2 = 1. 41421356237606 and
√3 = 1.7320508075688772
From the above value we clearly say that √2 and √3 are two irrational numbers because the decimal representations are non-terminating non-recurring. Also, √3 > √2
Hence, the two irrational numbers may be 1.501001612 and 1.602019

Try yourself: Which of the following numbers is an irrational number?

A.0.121212…
B.0.3333…
C.√9
D.√5

Operations on Real Numbers

We know that, “The collection of rational & irrational numbers together forms Real numbers”.

Both Rational & irrational numbers satisfy commutative law, associative law, and distributive law for addition and multiplication. However, the sum, difference, quotients and products of irrational numbers are not always irrational. If we add, subtract, multiply or divide (except by zero) two rational numbers, we still get a rational number. But this statement is not true for irrational numbers. We can see the example of this one by one

Rational Number + Rational Number = Rational Number

Let, a = (rational) and b = (rational),
=
=
=
= (rational number)

Rational Number – Rational Number = Rational Number

Let, a = (rational) and b = (rational)
=
=
= (rational number)

Rational Number X Rational Number = Rational Number

Example:

Let, a = (rational) and b = (rational)
Hence, × = (rational)

Rational Number / Rational Number = Rational Number

Let, a = Operations on Real Numbers (rational) and b = (rational)
divided by
i.e.,
Hence, ÷ = x = x 3

The sum and difference of a rational number and an irrational number is an irrational number.

Example:

Let, a = Operations on Real Numbers (rational) and b = √3 (irrational) then,
a + b = + √3 = (irrational)
a − b = − √3 = (irrational)

The multiplication or division of a non-zero rational number with an irrational number is an irrational number.

Example:

Let, a = Operations on Real Numbers (rational) and b = √2 (irrational) then,

ab = Operations on Real Numbers × √2 = (irrational)

Operations on Real Numbers = = × = (irrational)

If we add, subtract, multiply or divide two irrational numbers, we may get an irrational number or rational number.

Example:

Let two irrational numbers be
a = 3 + √2 and b = 3 − √2 then
a + b = ( 3 + √2 ) + ( 3 − √2 )
= 3 + √2 + 3 − √2
= 3 + 3
= 6 (rational)
Let two irrational numbers be
a = √3 + 1 and b = √3 − 1 then
A + b = (√3 + 1 ) + (√3 − 1)
= √3 + 1 + √3 − 1
= 2√3 (irrational)

Examples: Write which of the following numbers are rational or irrational.

(a) π − 2

(b) (3 + √27 ) − (√12 + √3)
(c) Operations on Real Numbers

(a) π − 2

We know that the value of the π = 3.1415
Hence, 3.1415 – 2 = 1.1415
This number is non-terminating non-recurring decimals.

(b) (3 + √27 ) − (√12 + √3)

On simplification, we get
( 3+ ) – ( + )
= 3 + 3√3 − 2√3 − √3
= 3 + √3 − √3
= 3, which is a rational number.

(c) Operations on Real Numbers

Here, 4 is a rational number and √5 is an irrational number. Now, we know that division of rational number and irrational number is always an irrational number.

Example: Add: 3 √2 + 6 √3 and √2 – 3√3
= (3 √2 + 6 √3 ) + (√2 – 3 √3 )
= (3 √2 + √2 ) + (6 √3 – 3 √3 )
= (3 + 1) √2 + (6 − 3) √3
= 4√2 + 3√3

Example: Multiply: 5√3 x 3√3

5√3 x 3√3
= 5 x 3 x √3 x √3
= 15 x 3 = 45

Try yourself:What is the value of the product of two irrational numbers?

A. Always irrational
B.Always rational
C.Can be rational or irrational
D. None of the above

Representation of √x for any positive integer x on the number line geometrically

We understand this method with the help of following steps. This construction shows that √x exists for all real numbers x > 0

Step I: Firstly mark the distance x from fixed point on the number line i.e. PQ = x

Step II: Mark a point R at a distance 1 cm from point Q and take the mid-point of PR.

Step III: Draw a semicircle, taking O as centre and OP as a radius.

Step IV: Draw a perpendicular line from Q to cut the semi-circle to find √x

Step V: Take the line QR as a number line with Q as zero.

Step VI: Draw an arc having centre Q and radius QS to represent √x on number line.

Representation of √x for any positive integer x on the number line geometrically

We can see this method with the help of example

Example: let us find it for x = 4.5, i.e., we find √4.5

(i) Firstly, draw a line segment AB = 4.5 units and then extend it to C such that BC = 1 unit.
(ii) Let O be the Centre of AC. Now draw the semi- circle with centre O and radius OA.
(iii) Let us draw BD from point B, perpendicular to AC which intersects semi-circle at point D.
Hence, the distance BD represents √4.5 ≈ 2.121 geometrically. Now take BC as a number line, draw an arc with centre B and radius BD from point BD, meeting AC produced at E. So, point E represents √4.5 on the number line.

Radical Sign: Let a > 0 be a real number and n be a positive integer, such that

(a) Representation of √x for any positive integer x on the number line geometrically = is a real number, then n is called exponent, and a is called radical and “√ ” is called radical sign.
The expression is called surd.

Example: If n = 2 then (4) = is called square root of 2.

Identities

Now we will list some identities which are related to square roots. You are familiar with these identities, which hold good for positive real number a and b. Let a and b be positive real numbers. Then,

Let’s solve some examples on the basis some of identities:

Examples: Simplify each of the following

(a) x
(b)
(c) ( √2 + √3 ) (√2 – √3)
(d) (5 + √5 ) (5 – √5 )

(a) x

We know that,
x =
=
= = ²
= (2⁵)
= 2¹
= 2

We know that,
=
=
=(3⁴)
= 3

(c) (√2 + √3 ) (√2 – √3)

(d) (5 + √5 ) (5 – √5 )

We know that,

Rationalising the Denominators

Looking at the value Rationalising the Denominators can you tell where this value will lie on the number line? It is a little bit difficult. Because the value containing square roots in their denominators and division is not easy as addition, subtraction, multiplication and division are convenient if their denominators are free from square roots. To make the denominators free from square roots i.e. they are whole numbers, we multiply the numerator and denominators by an irrational number. Such a number is called a rationalizing factor.

Note: Conjugate of Rationalising the Denominators is , and conjugate of ,

Let’s solve some examples on rationalizing the denominators:

Examples: Rationalise the denominator of the following

(a) Rationalising the Denominators

(b) Rationalising the Denominators

(c) Rationalising the Denominators

(d) Rationalising the Denominators

(a) Rationalising the Denominators

Rationalization factor for
Here, we need to rationalise the denominator i.e., remove root from the denominator. Hence, multiplying and dividing by
∴

(b) Rationalising the Denominators

We know that the conjugate of 4 + √2 = 4 – √2
∴

(c) Rationalising the Denominators

We know that the conjugate of √3 – √5 = √3 + √5
∴

(d) Rationalising the Denominators

We know that the conjugate of 5 + 3√2 = 5 – 3√2

Laws of Exponent for Real Numbers

Now we will list some laws of exponents, out of these some you have learnt in your earlier classes. Let a (> 0) be a real number and m, n be rational numbers.

(i) a^m X aⁿ = a^m+n

(ii) (a^m)ⁿ = a^mn

(iii) ⁼a^m-n

(iv) a^m X b^m = (ab)^m

^(v)a^-m = Laws of Exponent for Real Numbers

(vi) ( Laws of Exponent for Real Numbers ) ^-m= ()^m

Note: The value of zero exponent i.e. a° =1

Let us now discuss the application of these laws in simplifying expression involving rational exponents of real numbers.
Examples: Simplify each of the following
(i) (2)⁵ x (2)³
(ii) (4³)²
(iii) Laws of Exponent for Real Numbers
(iv) 7² × 6²
(v) 6^-2
(vi)
(vii) 3^3/2

(i) (2)⁵ x (2)³

We know that,
a^m x aⁿ = a^m+n
Hence,
(2)⁵ × (2)³ = (2)⁵⁺³= (2)⁸

(ii) (4³)²

We know that,
(a^m)ⁿ = a^mn
(4³)² = (4)^{3 ×2} = (4)⁶

(iii) Laws of Exponent for Real Numbers

We know that,
a^m/aⁿ = a^m-n
= = 5^3-2 = 5¹

(iv) 7² × 6²

We know that,
a^m x b^m = (ab)^m
(7)² × (6)² = (7 × 6)² = (42)²

(v) 6^-2

We know that,
a^-m =1/a^m
6^-2 = 1/6² = 1/36

(vi) Laws of Exponent for Real Numbers

We know that

(vii) 3^3/2

We know that

Try yourself:Which of the following best describes a number with a decimal representation like 0.3333…?

A.Finite decimal
B.Non-terminating non-repeating decimal
C. Terminating decimal
D.Non-terminating repeating decimal

Summary

1. Rational Numbers:

A number is classified as rational if it can be expressed as a fraction p/q where p and q are integers and q ≠ 0.
The decimal expansion of a rational number is either terminating or non-terminating but recurring.

2. Irrational Numbers:

A number is classified as irrational if it cannot be expressed as p/q, where both p and q are integers and q ≠ 0.
The decimal expansion of an irrational number is non-terminating and non-recurring.

3. Real Numbers:

The set of all rational and irrational numbers combined forms the collection of real numbers.

4. Operations with Rational and Irrational Numbers:

If r is rational and s is irrational, then:
r + s and r – s are irrational.
r × s and r / s (given r≠ 0) are irrational.

5. Identities for Positive Real Numbers:

For any positive real numbers a and b:

6. Rationalizing the Denominator:

To rationalize the denominator in terms like 1 / a + b multiply by the conjugate a – b / a – b.

7. Exponential Properties:

Let a > 0 be a real number and p and q be rational numbers. Then:

12. Short & Long Answer Questions- Improvement in Food Resources

February 17, 2026 by khushikhanera

Very Short Answers Type Questions

Ques 1: Name any two fodder crops.
Ans: Berseem, oats or sudan grass are raised as food for the livestock, called fodder crops.

Ques 2: What do you understand b.y photoperiod of sunlight?
Ans: Photoperiod are related to the duration of sunlight required for plant growth.

Ques 3: Name two kharif crops.
Ans: Paddy and soyabean.

Ques 4: Name two rabi crops.
Ans: Wheat and gram.

Ques 5: Define hybridisation.
Ans: Hybridisation refers to crossing between genetically dissimilar plants, to obtain, better variety of crops.

Ques 6: What are genetically modified crops?
Ans: By introducing a gene with required characters into a crop for its improvement is called genetically modified crop.

Ques 7: “Shorter the duration of the crop from sowing to harvesting, the more economical is the variety”. Give reason for this.
Ans: Due to short duration of crop growth, farmers can grow more crops in a year, and reduce the cost of drop production.

Ques 8: Name different types of crop production practices involved in India.
Ans: They are (a) no cost production
(b) low cost production
(c) high cost production.

Ques 9: Who provides nutrients to plants?
Ans: Nutrients to plants are provided by air, water and soil.

Ques 10: What are macro-nutrients?
Ans: The nutrients required by plants in larger quantity is called macro-nutrients. They are nitrogen, phosphorus, potassium, calcium, magnesium and sulphur.

Ques 11: Name the nutrients that plant obtain from air and water.
Ans: Air – Carbon and oxygen Water- Hydrogen and oxygen

Ques 12: State the difference between compost and vermi-compost.
Ans: The compost is obtained by decomposition of organic waste like animal excreta, plant waste etc. naturally due to decomposition by bacteria.
Vermi-compost: To hasten the process of decomposition redworms are added to this organic matter to obtain compost.

Ques 13: Name any two weeds.
Ans: Parthenium and Xanthium.

Ques 14: What causes disease in plants?
Ans: It is caused by pathogens such as bacteria, fungi and viruses.

Ques 15: Name two Indian cattle.
Ans: Bos indicus – cows 4 Bos bubalis – buffaloes.

Ques 16: Name two exotic breeds of cattle.
Ans: Jersey and Brown Swiss

Ques 17: Name two variety of food required for milch animals.
Ans: • Maintenance requirement – food required to keep animal healthy
• Milk producing requirement – food required for increased lactation Animal food includes roughage and concentrate also.

Ques 18: State the meaning of capture fishing and culture fishing.
Ans: Capture fishing: It is done from natural resources.
Culture fishing: It is done by fish farming.

Ques 19: Name four marine fish varieties.
Ans: Pomphret, mackerel, tuna and sardines.

Ques 20: What is apiculture?
Ans: Keeping bee for obtaining honey commercially is called apiculture.

Ques 21: Name the products obtained from apiculture.
Ans: Honey and wax both are obtained from apiculture.

Short Answers Type Questions

Ques 1: What are the major group of activities involved for improving of crop yields?
Ans: • Crop variety improvement
• Crop production improvement
• Crop protection improvement

Ques 2: What are the different ways/ methods of hybridisation?
Ans: Hybridisation can be
• Intervarietal – between different varieties of crops
• Interspecific – between two species of same genus
• Intergeneric – between two different genera

Ques 3: What are the main characters required in a crop during its improvement practices?
Ans: The useful characters that are required in a crop during its improvement:
(a) Disease resistance
(b) Response to fertilizer
(c) Product quality
(d) High yield.

Ques 4: State the difference between macro-nutrients and micro-nutrients.
Ans:

Macro-nutrients	Micro-nutrients
These are required by crops in larger quantity.	These are required by crops in very small quantity.
Six macro-nutriets are: Nitrogen, phosphorus, potassium, calcium, magnesium and sulphus.	Seven micro-nutrients are: Iron, manganese, boron, zinc, copper, molybdenum and chlorine.

Ques 5: How do deficiency of nutrients affect the crop?
Ans: Deficiency of any nutrient affects physiological processes in plants including reproduction, growth and susceptibility to diseases.

Ques 6: State the difference between manure and fertilizer.
Ans:

Manure	Fertilizer
It consists of organic matter.	It consists of inorganic matter.
Prepared from animal excreta and plant waste.	It is prepared commercially from chemicals.
Its use causes no pollution.	It caused pollution in soil and water.

Ques 7: What are the harmful effects of fertilizer? .
Ans: It causes soil and water pollution. Continuous use can also destroy soil fertility.

Ques 8: What is organic farming?
Ans: It is the farming in which no chemical fertilizers, pesticides or herbicides are used. But uses all organic matter for its growth like manure, neem leaves as pesticides and for grain storage.

Ques 9: State the preventive and control measures used before grains are stored.
Ans: • Cleaning of the grains
• Proper drying of the produce in sunlight, there should be no moisture.
• Fumigation of produce using chemicals that kills pest.

Ques 10: Name few varieties of bees used for commercial honey production.
Ans: Apis cerana indica – Indian bee
A. dorsata – rock bee (local varieties)
A. florae – the little bee
A. mellifera – Italian bee variety

Ques 11: What decide the quantity and quality of honey production in apiary?
Ans: For quality of honey: The pasturage, f.e., the kind of flowers available to the bees for nectar and pollen collection will determine the taste of the honey. For quantity of honey: Variety of bee used for the collection of honey. For example, A. mellifera is used to increase yield of honey.

Ques 12: How are crops useful to us? What do they provide?
Ans: Crops provide us food for our daily body nutrient. Carbohydrate for energy
requirement – Cereals such as wheat, rice, maize.
Protein for body building — Pulses like gram, lentil
Fats for energy — Oil seed like mustard, sunflower
Vitamins and minerals — From vegetables, spices and fruits
Fodder crops — For livestocks

Ques 13: What are the factors for which variety improvement of crop is done?
Ans: (a) Higher yield: It increases production of crop.
(b) Biotic and abiotic resistance: Crop should be resistant to biotic factors
like diseases, insects, pests and abiotic factor like drought, salinity, heat, cold, frost and water logging.
(c) Change in maturity duration: Short-duration maturity allows farmer to grow more crops in a year and reduces the cost of crop production.
(d) Wider adaptability: Crop’should be able to adapt to changing environmental conditions.
(e) Desirable agronomic characteristics: The tallness and dwarfness of crop. Dwarfness is required for cereals, so that less nutrients are consumed.

Ques 14: Name the sources and the nutrients supplied by them to the plants.
Ans:

Source	Nutrients
Air	Carbon, oxygen
Water	Hydrogen, oxygen
Soil	Macro- nutrients (six)
	Nitrogen, phosphorus, potassium, calcium, magnesium, sulphur
	Micro- nutrients (seven)
	Iron, manganese, boron, zinc, copper, molbdenum, chlorine

Ques 15: What are manures? Give its classification.
Ans: Manures contain large ‘ quantities of organic matter and supplies small quantities of nutrients to the soil. It is prepared naturally by the decomposition of animal waste, excreta and plant waste.
• It helps in the soil enrichment with nutrients.
• It helps in improving the soil structure.
• It helps in increasing the water holding capacity in sandy soils.
• In clayey soils it helps in the water drainage and prevent water logging. Manure is classified based on the kind of biological material used to make it as :
(i) Compost
(ii) Vermi-compost
(iii) Green manure
(i) Compost: The farm waste and livestock excreta, along with vegetable waste, sewage waste, weeds, straws etc. are allowed to decompose in a pit is called compost. The compost is rich in nutrients.
(ii) Vermi-compost: When the above given matter is allowed to decompose in the pit along with some earthworms, the decomposition speeds up and is called vermi-composting.
(iii) Green manure: Some plants like sun-hemp or guar are grown and then mulched by ploughing them into the soil. This is done before the sowing of crop seeds into the field.
These green plants present in the soil acts as green manure which enriches the soil in nitrogen and phosphorus.

Ques 16: What are fertilizers? Excess use of fertilizers is not advisable, explain?
Ans: Fertilizers are obtained artificially on commercial basis. It is a chemical which contains the nutrients required for the crop to grow. Fertilizers supply various nutrients as they are nutrient specific e.g.-urea provides nitrogen. Mixed fertilizer provides any two mixture of nutrients. They are expensive but their use yield large production hence are a factor of high cost farming.
Excessive use of fertilizers are not advisable as:
(a) It leads to soil and water pollution.
(b) It can destroy the fertility of soil. As the soil is not replenished, micro¬organisms in the soil are harmed by fertilizers.

Ques 17: What are the different patterns of cropping?
Or
What are the different cropping systems?
Ans: Different ways/patterns / systems of growing crop’s are:
(a) Mixed cropping
(b) Inter-cropping
(c) Crop rotation.
Mixed cropping: It is a method in which two or more crops grow simultaneously on the same piece of land.
Example, Wheat + grain, wheat + mustard or groundnut + sunflower.
This helps in the reduction of risk factor and provides insurance against failure of one of the crops.
Inter-cropping: It is a method of growing two or more crops simultaneously on the same field in a definite patterns. A few row of one crop alternate with a few rows of second crop.
Example, soyabean + maize or bajra + lobia
Crop rotation: The growing of different crops on a piece of land in a pre¬planned succession is known as crop rotation.
The availability of moisture and irrigation facility decides the choice of crop to be cultivated after one harvest.

Ques 18: How does insect pests attack the plant and affect it?
Ans: Insect pests attack the plants in three ways:
1. They cut the root, stem and leaf.
2. They suck the cell sap from various parts of the plant.
3.They bore into stem and fruits.
This way they affect the health of the crop and reduces yield.

Ques 19: Give different methods of weed control.
Ans: Weeds can be controlled by different methods:
(a) Weedicides: These are the chemicals sprayed on the weeds to kill them. Excessive use is poisonous and causes environmental pollution.
(b) Mechanical removal: In this method weeds are uprooted by removing manually or by machines.
(c) Preventive methods: Proper seed bed preparation, timely sowing of crops, intercropping and crop rotation helps in weed control.

Ques 20: What are the new variety/traits obtained by cross breeding of Indian and exotic breeds of poultry?
Ans: The new variety/traits obtained by cross breeding of Indian and exotic breeds of poultry are:
1. Number and quality of chicks
2. Dwarf broiler parent for commercial chick production
3. Summer adaptation capacity/tolerance to high temperature
4. Low maintenance requirements
5. Reduction in the size of the egg-laying bird with ability to utilise more fibrous and cheaper diet, formulated using agricultural by-products

Ques 21: State the difference between egg-layers and broiler.
Ans:

Egg-layers	Broiler
They are fed on protein-rich feed.	They are fed on vitamin-rich supplementary feed for good growth rate.
Used for laying eggs.	Used for meat purposes. Lot of protein included in the diet.

Also read: NCERT Exemplar: Improvement in Food Resources

Long Answers Type Questions

Ques 1: What are the various methods of irrigation in India?
Ans: Most of agriculture in India is rain-fed, several different kinds of irrigation system are adopted to supply water to agricultural lands. The resources are- wells, canals, rivers and tanks.
• Wells: Dug wells and tube wells. In dug wells water is collected from water— bearing strata.
• Tubewells: Can tap water from deeper strata.
• Canals: Most extensive irrigation system. Canals receive water from reservoirs or rivers. The main canal is divided into branch canals having further distributaries to irrigate fields.
• River lift system: Water is directly drawn from the river for supplementing irrigation in areas close to rivers.
• Tanks: These are small storage reservoirs, which intercept and store the run-off of smaller catchment areas.

Ques 2: Large amount of food grains get spoiled every year in India due to improper storage of food grains. How can this be avoided?
Ans: Food grains get spoiled by insects, fungi, rodents, bacteria, moisture, temperature in the place of storage.
Storage losses can be minimised by following preventive and control measures.
1. The seeds/grains that are to be stored should be dry, with no moisture in it.
2. The grains should be cleaned.
3. The grains should be fumigated using chemicals that kills pest.
4. The storage houses should be water proof.
5. The grains should be stored in sealed gunny bags or metal containers.
6. The bags should be stacked in order i.e. in pile for proper fumigation, and should be kept few centimetres away from the wall.
7. The ventilators if any should be closed tightly, to avoid birds visiting the storage house and destroying the grains.
8.The walls and the floor should be water-proof with no holes in it, to avoid rodents, pests.

Ques 3: Explain different types of fisheries.
Ans: The different types of fisheries are marine fisheries, inland fisheries, capture fishing, mariculture and aquaculture.
• Marine fisheries: Marine fishes are caught using fishing nets. Large schools of fishes is located by satellites. Some are farmed in sea water.
• Mariculture: Marine fishes are cultured in seawater this culture of fisheries is called mariculture.
• Inland fisheries: The fisheries done in fresh water resources like canals, ponds, reservoirs and rivers is called inland fisheries.
• Capture fishing: It is done in sea-water, estuaries and lagoons.
• Aquaculture: Culture of fish done in different water bodies is called aquaculture.

Ques 4: What are the practices used for dairy industry?
Ans: The practices required for raising daily animals to get the optimum yield are:
(i) Shelter.
(ii) feeding.
(iii) rearing of animals.
(iv) breeding.
(i) Shelter: The shelter should be clean, spacious and airy.
(ii) Feeding: Proper food is essential for dairy animals, two types of food are roughage and concentrates. Proper feed at proper time is required for dairy animals.
(iii) Rearing of animals: Providing them proper health care and protection from pathogens, diseases and proper vaccination.
(iv) Breeding: The crossing of different variety of milch animals to obtain a breed that can produce more yield of milk.

Value-based Questions

Ques 1: A group of Eco Club students made a compost pit in the school, they collected all bio-degradable waste from the school canteen and used it to prepare the compost.
(a) Name two waste that can be used for the compost and two wastes obtained from canteen which cannot be used for the compost making?
(b) What is the other important component required for making the compost?
(c) What values of Eco Club students are reflected in this act?
Ans: (a) Two waste used for compost are vegetable peels and fruit peels. Two waste material that cannot be used as compost are polythene bags and plastic items.
(b) Bacteria and fungi present in soil are the other important component for making compost.
(c) Eco Club students reflect the value of group work, responsible citizens.

Ques 2: Surjeet read an article in the newspaper that prolonged and excess use of pesticides and fertilizers leads to cancer in human beings. He also saw the increased number of cancer patients in his town. He started educating the farmers in his town to minimize or stop the use of chemicals in farming and adopt the organic farming.
(a) What is the most common pesticide used in our country?
(b) Give one difference in organic farming and chemical farming.
(c) What value of Surjeet is seen in the above act?
Ans: (a) The common pesticide is DDT.
(b) Organic farming: It is a farming system with minimal or no use of chemicals as fertilizers, herbicides, pesticides etc.
Chemical farming: Generally, chemicals are used as fertilizers, herbicides, pesticides etc. to increase crop yield.
(c) Surjeet showed the value of responsible person, leadership quality, initiative taker and a concerned citizen

Ques 3: Large number of Bhetki fish died and got crushed in the turbines of hydroelectric power stations while they migrated from river to sea. The environmentalist gave power plant the solution to this problem. Now all Bhetki fish is removed with the help of special technique and hence do not enter the turbines to crush and die.
(a) What is pisciculture?
(b) Suggest two different varieties of fish.
(c) What value of environmentalist is reflected in the above case?
Ans: (a) The rearing of fish on large scale is called pisciculture.
(b) Two varieties of fish are bony and cartilaginous.
(c) Environmentalist showed the value of concerned and caring individuals.

Ques 4: A group of gardening club students prepared a kitchen garden in the school campus and did organic farming to grow the vegetables. Then the students presented their group work in the assembly to spread the awareness and make students understand the importance of organic products.
(a) What is horticulture?
(b) What is green manure?
(c) State the values of gardening club students.
Ans: (a) Production of vegetables and fruits commercially is called horticulture.
(b) The green plants like guar or sun hemp are turned into the soil which enriches the soil with nitrogen and phosphorus and is called green manure.
(c) Values of gardening club students are aware individuals and responsible behaviour.

11. Short & Long Answer Questions- Sound

February 17, 2026 by khushikhanera

Very Short Answer Type Questions

Ques 1: Is sound wave longitudinal or transverse?
Ans: Sound wave is longitudinal in nature.

Ques 2: What is the relation between frequency (v) and time period of a sound wave?
Ans: v = 1/T
Frequency is inversely proportional to time period.

Ques 3: In which of the three media air, water or steel does sound travel the fastest?
Ans: Sound travels fastest in steel.

Ques 4: Which has a higher pitch—the sound of a whistle or that of a drum?
Ans: The sound of whistle has higher pitch.

Ques 5: What is pitch?
Ans: The way our brain interprets the frequency of an emitted sound is called the pitch.

Ques 6: How can we distinguish one sound from another having the same pitch and loudness?
Ans: The quality or timber of sound helps us to distinguish one sound from another having the same pitch and loudness.

Ques 7: What is the audible range of frequency for human beings?
Ans: The audible range of frequencies for human beings is 20 Hz to 20,000 Hz.

Ques 8: What is one Hz?
Ans: Hz is the unit of frequency, called as Hertz. One Hertz is equal to one cycle per second.

Ques 9: Define speed of sound.
Ans: The speed of sound is defined as the distance travelled per unit time by compression or rarefaction.

Ques 10: Find the frequency of a wave whose time period is 0.002 second.
Ans: Frequency = 1/ Time preiod
Frequency = 1/0.002 = 500 Hz

Short Answer Type Questions

Ques 1: What is a medium? Give two examples.
Ans: The matter or substance through which sound is transmitted is called a medium. It can be solid, liquid or gas. Example, air, water, metals.

Ques 2: Define wave-motion.
Ans: A wave is a disturbance that moves through a medium when the particles of the medium set neighbouring particles into motion. The particles of the medium do not move forward but the disturbance is carried forward.

Ques 3: What is ‘sonic boom’?
Ans: When an object just attains a supersonic speed, it causes shock waves in air. As a result there is large change in air pressure. This results in sonic boom.

Ques 4: Why does sound become faint with distance?
Ans: Sound is a form of energy. As it moves away from the source its amplitude as well as its loudness decreases. The energy also get transformed in vibration of the particles of the medium.

Ques 5: Why do we say that sound waves are longitudinal?
Ans: Longitudinal waves need medium for propagation. The sound energy travel in the same line as the particles oscillate.
It forms compression and rarefaction for the longitudinal wave motion. Sound wave shows all the characteristics of longitudinal wave so it is called as longitudinal wave.

Ques 6: Differentiate between longitudinal wave and transverse wave.
Ans: Short Answer Type Questions

Ques 7: What is crest and trough?
Ans: When a wave is propagated as represented below. A peak is called the crest and a valley is called the trough of a wave.
Short Answer Type Questions

Ques 8: The maximum oscillation disturbance of particles of air forms crest and trough. What is echo? Why don’t we get echo in small room?
Ans: The distinct sound heard after reflection of sound from the source is called echo. For echo, the distance of reflecting surface from the source should be more than 17.2 m.

Ques 9: What is velocity of sound? Why does sound travel faster in summer season than in winter?
Ans: Velocity of sound is- the speed of sound in a given medium at a given temperature. As the temperature increases the speed of sound also increases, hence in summer the sound travels faster than in winter.

Ques 10: Draw a graphical representation of the wave shape for
(a) low pitched sound
(b) a high pitched sound.
Ans:
Short Answer Type Questions

Ques 11: Give two applications of echo/reflection of sound.
Ans: (i) Ships use reflection of sound technique “SONAR” which helps in locating the depth, distance, direction and speed of underwater objects.
(ii) Ceilings of concert halls are curved so that sound after reflection reaches all comers of the hall.

Ques 12: Define amplitude time period and frequency of sound wave.
Ans: Amplitude: The magnitude of the maximum disturbance in the medium on either side of the mean value is called amplitude of the wave. Its unit is meter.
Time Period: The time taken by two consecutive compressions or rarefactions to cross a fixed point is called the time period of the wave.
Frequency: The number of oscillation, occurring per unit time is called the frequency of sound wave.

Ques 13: A sound wave causes the density of air at a place to oscillate 1200 times in 2 minutes. Find the time period and frequency of the wave.
Ans: Frequency = 1200/2 × 60 = 10Hz
Time period = ? Frequency = 1/T
∴ T = 1/Frequency = 1/10 = 0.1 s.

Ques 14: Give 3 uses of ultrasound.
Ans: Use of ultrasound:
1. Ultrasound is used to detect cracks and flaws in metal blocks.
2. It is used in ‘echo-cardiography’, the ultrasonic waves are made to reflect from various parts of the heart and form the image of the heart.
3. It is used in ‘ultrasonography’, to detect the image of organs or to detect the abnormalities in the organs. It is also used to examine the foetus during pregnancy to detect congenital defects.

Ques 15: What is the function of middle ear?
Ans: Middle ear consist of three small bones called hammer, anvil and stirrup. These three bones receive the sound vibrations and increase the strength of these vibrations to amplify the vibrations received by ear-drum. These amplified vibrations are furthgr passed to the inner ear.
A ship sends out ultrasound that return from the seabed and is detected after 3.42 s.

Ques 16: If the speed of ultrasound through seawater is 1531 m/s. What is the distance of the seabed from the ship?-
Ans: Time between transmission and detection t = 342 s.
Speed of ultrasound in seawater = 1531 m/s.
Distance travelled by the ultra sound = 2 × deoth of sea = 2d
2d = speed of sound × time
= 1531 × 3.42 = 5236 m
∴ 2d = 5236 m
∴ d = 5236/2 = 2618 m.
The distance of the seabed from the ship is 2618 m.

Ques 17: Distinguish between tone, note and noise.
Ans: Tone: A sound of single frequency is called a tone.
Note: The sound which is produced due to a mixture of several frequencies is called a note.
Noise: The sound which is produced due to a mixture of several frequencies but is unpleasant to the ear is called noise.

Ques 18: Establish the relationship between speed, wavelength and frequency of sound.
Ans: Speed of sound —» The distance travelled by a wave or a point on a wave (compression or rarefaction) per unit time.
Speed v = Distance/Time
v = λ/T
Distance = wavelength of the sound wave, it is the distance travelled by the sound wave in one time period (T) of the wave.
∴ v = λ/T (as v = 1/T)
∴ v = λv, Frequency = 1/Time period
Speed = Wavelength * Frequency.

Ques 19: Which wave property determines
(a) loudness?
(b) pitch?
Name the characteristic of the sound which help you to distinguish your friend’s voice while talking in a dark room.
Ans: (a) Loudness is determined by amplitude.
(b) Pitch is determined by frequency.
The quality or timber of sound helps us to distinguish our friend’s voice while talking in a dark room.

Ques 20: A sound produces 13 crests and 15 troughs in 3 seconds. When the second crest is produced the first is 2 cm away from the source? Calculate.
(a) the wavelength
(b) the frequency
(c) the wave speed.
Ans:

(a) Wavelength = distance between two consecutive crests or troughs is 2 cm.
(b) Frequency = Number of troughs/Time = 15/3 =5 Hz
(c) Wave speed = Distance/Time
Distance travelled by weve = 15 * 2 = 30cm
Time = 3 seconds
∴ Wave speed = 30/3 = 10 cm/s.

Long Answer Type Questions

Ques 1: Sound cannot travel in a vacuum. Describe an experiment to demonstrate this.
Ans: Sound is a mechanical wave and needs a material medium to propagate. It cannot travel in a vacuum and can be shown by the following experiment.
• Take an electric bell and an airtight glass bell jar. The electric bell is suspended inside the airtight bell jar. Switch ‘ON’ the electric bell.
• Now, connect the bell jar to the vacuum pump.
• Pump out the air from the jar, the sound becomes fainter, although the same current passes through the bell.
• Pump out some more air from the jar, a very feeble sound is heard.
• When the air is completely removed from the jar, no sound is heard.
Long Answer Type Questions

Ques 2: Given that sound travels in air at 340 m/sec, find the wavelength of the waves in air produced by 20 kHz sound source. If the same source is put in a water tank, what would be the wavelength of the sound waves in water? (Speed of sound in water = 1480 m/s.)
Ans: Speed of sound in air = 340 m/s.
Frequency = 20 kHz = 20* 10³ Hz
Wavelength = ?
∴ Speed = Wavelength × Frequency
v = λv
Long Answer Type Questions
Speed of sound in water = 1480 m/s
Frequency = 20 × 10³Hz
Wavelength = ?
∴ Speed = Wavelength × Frequency
Wavelength = Speed /Frequency
= 1480/20 10³ = 0.074 m.

Ques 3: A child watching Dussehra celebration from a distance sees the effigy of Ravana burst into flames and hears the explosion associated with it 2 sec after that. How far was he from the effigy if the speed of sound in air that night was 335 m/sec?
Ans: Speed of sound in air = 335 m/s.
time required to reach the sound = 2 sec
distance of the source of sound = ?
∴ Speed = Distance/Time
∴ Distance = Speed × Time
= 335 × 2 sec
= 670 m.

ACTIVITY-BASED QUESTIONS
Ques 1: • Take a tuning fork and set it vibrating by striking its prong on a rubber pad. Bring it near your ear.
• Do you hear any sound?
• Touch one of the prongs of the vibrating tuning fork with your finger and share your experience with your friends.
• Now, suspend a table tennis ball or a small plastic ball by a thread from a support. Touch the ball gently with the prong of a vibrating tuning fork.
• Observe what happens and discuss with your friends.

Ans: • Yes, we heard sound.
• If we touch the ball with tuning fork set into vibration, the ball gets displaced from its mean position and starts moving.

Ques 2: • Fill water in a beaker or a glass up to the brim. Gently touch the water surface with one of the prongs of the vibrating tuning fork.
• Next dip the prongs of the vibrating tuning fork in water. .
• Observe what happens in both the cases.
• Discuss with your friends why this happens.
• Arrange them on a table near a wall.
• Keep a clock near the open end of one of the pipes and try to hear the sound of the clock through the other pipe.
• Adjust the position of the pipes, so that you can best hear the sound of the clock.
• Now, measure the angles of incidence and reflection and see the relationship between the angles.

Ans: In both the cases, sound will be produced by the tuning fork which produces ripples. But in case
(1) ripples are produced which will move up and down and in case
(2) ripples are produced which will move in sideways.

Ques 3: • Take a slinky. Ask your friend to hold one end. You hold the other end. Now stretch the slinky and give it a sharp push towards your friend.
• What do you notice? If you move your hand pushing and pulling the slinky alternatively, what will you observe?
• If you mark a dot on the slinky, you’ll observe that the dot on the slinky will move back and forth parallel to the direction of propagation of the disturbance.

Ans: When we give a small jerk a hump is produced and this travels forward. When we give a sharp push continuous disturbance is produced. When we give a push or pull to the slinky, slinky starts moving in the forward and backward direction parallel to the direction of propagation of the disturbance.

Ques 4: • Take two identical pipes. The length of the pipes should be sufficiently long.

• Lift the pipes on the right .vertically to a small height and observe what happens.
Ans: (i) Reflection of sound is similar to reflection of light i.e. Angle of incidence = Angle of reflection.
(ii) If we lift the pipe vertically to a small height, well not be able to hear the sound through the other end of the pipe because Angle of incidence * Angle of reflection. Therefore the reflected ray will not travel through the pipe B.

VALUE-BASED QUESTIONS
Ques 1: Raj noticed that his pet dog was frightened and trying to hide in safe place in his house when some crackers were burst in the neighbourhood. He realized the problem and he decided not to burst crackers during diwali or for any other celebrations.
(a) What must be the range of crackers sound?
(b) Name two diseases that can be caused due to noise pollution.
(c) Name the values of Raj reflected in above act.
Answer: (a) The range of crackers sound must be between 20 Hz to 20 kHz.
(b) Two diseases that can occur due to noise pollution are heart attack and high blood pressure.
(c) Raj reflects the value of respecting sensitivity for animals and caring for animals.

Ques 2: It is not advisable to construct houses near airports, in spite of that many new residential apartments are constructed near airports. Sumit files RTI and also complains the municipal office about the same.
(a) Why one should not reside near airport?
(b) Name other two places where there is noise-pollution.
(c) What value of Sumit is reflected in this act?
Ans: (a) The landing and taking off of the air-planes causes lot of noise pollution which may lead to deafness, high blood pressure and other health problems.
(b) The other two places where there is noise-pollution is, residing near the heavy traffic routes and railway stations or lines.
(c) Sumit shows participating citizen and moral responsibility values.

10. Short Question Answer: Work and Energy

February 17, 2026 by khushikhanera

Q1: When the work is said to be done?
Ans: When a force acts on an object and moves it in the same direction that of force then work is said to be done.

Q2: What will be the expression for the work done when a force acts on an object in the direction of its motion.
Ans: Work done = Force × Displacement
If W is the work done, F is the force applied on object and d is the displacement, then the expression of work done will be
W = F × d

Q3: Explain 1 joule of work done.
Ans: When a force of 1 N (Newton) is applied on an object and that object displaces upto a distance of 1 m (meter) in the same direction of its displacement, then 1 joule (J) of work is done on the object.

Q4: How much work is done in ploughing a 15 m long field when a pair of bullocks applies a force of 140 N on the plough?
Ans: Since Work done (W) = Force (F) × Displacement (d)
Hence, Work done in ploughing (W) = 140 N × 15 m = 2100 J

Q5: The force acting on the object is 7 N, and the displacement of the object occurs in the direction of the force is 8 m. Suppose that force acts on the object through displacement, then how much work was done in this case?
Ans: As we know, Work done (W) = Force (F) × Displacement (d)
Thus, Work done in the given case (W) = 7 N × 8 m = 56 J

Q6: Define kinetic energy of an object.
Ans: The kinetic energy of an object is a kind of mechanical energy that exists in the object due to its state of motion (movement).

Q7: Write down the kinetic energy expression of an object.
Ans: If m is the mass of an moving object and v is its velocity, then the expression of its kinetic energy (KE) will be
K.E = 1/2mv²

Q8: Define power.
Ans: The rate by which work is done refers to power. It is expressed by P.
Power = Work done/Time
P = W/t

Q9: What is 1 watt of power?
Ans: When an object is doing work at the rate of 1 J/s, then the power of that body or object is 1 watt (where watt is the unit of power).

Q10: An object is thrown at an angle to the ground, moves along a curve and falls back to the ground. The start and end points of the object path are on the same horizontal line. How much work is done by the gravity on that object?
Ans: There must be a displacement to calculate the work, but since the vertical displacement in this case is zero (because the start and end points are on the same horizontal line), the work done by gravity is zero.

Q11: How does the state of energy get changed when a battery lights up a bulb?
Ans: The chemical energy of the battery is converted into heat and light energy of the bulb in the given case.

Q12: Calculate the work done by the force that changes the velocity of a moving body from 5 ms^-1 to 2 ms^-1. The body has a mass of 20 kg.
Ans: Since work done by force = Change in the kinetic energy of the moving body
Therefore, Work done by force =

= 1/2 x 20 ( 5 ²– 2²) = 10 x (25-4) = 10 x 21 = 210 J

Q13: An object having 10 kg weight is moved from point A to point B on the table. If the distance between A and B is horizontal, what work does gravity do to the object? Give the reason for the answer.
Ans: Since the work done by gravity on the object depends on the change in the vertical height of the object, the vertical height of the object will not change. Because the connection level of A and B is at the same height, the work done is zero.

Q14: The potential energy of an object decreases gradually in a free fall. How does this violate the law of conservation of energy?
Ans: This does not violate the law of conservation of energy, because the potential energy of an object in free fall gradually decreases with gradual changes until the kinetic energy of the object maintains the state of free fall, that is, the total energy of the object remains conserved.

Q15: What energy conversion occurs when riding a bicycle?
Ans: Our muscle energy is converted into mechanical energy while riding a bicycle.

Q16: Does energy transfer occur when you push a huge rock with all your strength without moving it? Where did the energy you applied go?
Ans: As long as you push a big rock with all your strength and do not move it, energy transfer will not occur, because cell energy is only used for muscle contraction and relaxation, and also for releasing heat (sweating).

Q17:A household uses 250 units of energy in a month. How much energy is used by that house in joules?
Ans: Energy consumption by a house = 250 kWh
Since, 1 kWh = 3.6 × 10⁶ J
hence, 250kWh= 250 × 3.6 × 10⁶ = 9 × 10⁸ J

Q18: The output power of the electric heater is 1500 watts. How much energy does it consume in 10 hours?
Ans: Power of electric heater (p) = 1500W = 1.5kW
Energy = Power × Time = 1.5kW × 10 hours = 15 kWh

Q19: An object of mass m moves at a constant speed v. How much work does the subject need to do to make it stable?
Ans: For an object to be stationary, the work done must be equal to the kinetic energy of the moving object.
The kinetic energy of any object is equal to
K.E=1/2mv², where m is the mass of the body and v is its velocity.

Q20: Sony said that even if different forces act on the object, the acceleration of the object can be zero. Do you agree with her, if yes, why?
Ans: Yes, we agree with Soni, because the displacement of an object becomes zero when many balancing forces act on that object.

Q21: Calculate the energy (in kilowatt hours) consumed by four 500 W devices in 10 hours.
Ans: Since, Energy = Power × Time
Hence, Energy consumed by four 500 W devices in 10 hours
= 4 × 500 × 10
= 20000 Wh
= 20 kWh

Q22: Free-falling objects will eventually stop when they hit the ground. What will happen to their kinetic energy?
Ans: The object will eventually stop after it hits the ground in free fall, because its kinetic energy will be transferred to the ground when it hits the ground.

Q23: A large force acting on an object, and the displacement of that object is zero, what will be the work done?
Ans: The work done on the body is defined as the force exerted on the body that causes a net displacement of the body.
Work done = Force x Displacement
If the force does not cause any displacement, the work done to the object is zero.

Q24: Write some differences between kinetic and potential energy.
Ans: Differences between kinetic and potential energy:

Q25: Describe the law of conservation of energy.
Ans: The law of conservation of energy says that:

Energy cannot be produced or destroyed. It can only be transformed from one form to another.
The energy of the universe is constant.

Q26: A person weighing 50 kg climbs the stairs with a height difference of 5 meters, within 4 seconds.
(a) What kind of work is done by that person?
(b) What is the average power of that person?
Ans: Mass of the man = 50 Kg
Distance moved by that man = 5 meter
Time taken to cover the given distance = 4s
(a) Work Done = Force Acceleration
In this case, the increase in Potential energy = Work done =Mgh
=50×10×5
=2500 J
(b) Power = Work Done /Time Taken =2500/ 4=625 Watts

Q27: Write differences between power and energy.
Ans: Differences between power and energy are given below:

Q28: Write down the expressions for
(a) Potential energy of an object
(b) Kinetic energy of an object
Ans:
(a) The expression for Potential energy of an object = P.E = mgh
Where, m = Mass of Body
g = Acceleration due to gravity
h = Height
(b) The expression for Kinetic energy of an object = 1/2mv²
Where, m = Mass of body
v = Velocity of body

Q29: If a force of 12.5 N is applied to complete a work of 100 J, what is the distance covered by the force?
Ans: W = Work = 100 J
F = Force = 12.5 N
And S is the distance moved or displacement
Since, Work done = Force Displacement
W = FS
100 =12.5 × S
100/12.5 = S
8 m=S (Displacement)

Q30: A car weighing 1800 kg is moving at a speed of 30 m/s when braking. If the average braking force is 6000 N, it is determined that the vehicle has traveled to a standstill distance. What is the distance at which it becomes stable?
Ans: M = Mass of the car = 1800 Kg
V = Velocity of the car = 30 m/s
F = Force applied while braking = 6000 N
KE=1/2mv²
KE =121800×900
KE=810000 J
KE of car = Work done by the car = Force Displacement
810000=6000× Displacement
810000/6000= Displacement
135 m= Displacement

Q31: What do you understand about average power?
Ans: The agent may not always be able to complete the same amount of work in a given time period. In other words, the power of this work will change over time. Therefore, in this case, we can take the average power of the work done by the body per unit time (that is, the total energy consumed divided by the total time).

Q32: Take a look at the steps below. Based on your understanding of the word “work”, prove whether the work will proceed.

Suma swims in the pond.
The donkey carries a heavy load.
The windmill draws water from the well.
Green plants perform photosynthesis.
The trains are pulled by engines.
Drying food grains in the sun.
Sailing boats are powered by wind.

Ans: The work is said to be done when a force acts on an object and moves in the direction of the force. According to this explanation, the following activities were taken in which work will be proceeded:

Suma swims in the pond.
The donkey carries a heavy load.
The windmill draws water from the well.
The trains are pulled by engines.
Sailing boats are powered by wind.

Q33: The law of conservation of energy is explained by discussing the energy changes that occur when we move the pendulum laterally and swing it. Why does the pendulum eventually stop? What happens to the energy and does it violate energy conservation law?
Ans: Bob will eventually stop due to the friction created by the air and the rigid support that holds the thread in place. This does not violate the law of conservation of energy, because mechanical energy can be converted into another unusable form of energy for some useful work. This energy loss is called energy dissipation.

Q34: Get the expression of the potential energy of an object. Calculate PE for a body of 10 kg which is resting at a height of 10 m.
Ans: The potential energy of an object with mass = m kg, at height above the ground =h m
Gravitational force of attraction on that body = mgN
To lift that body to B height at h m above the ground.
Force applied to lift this body with a constant velocity =mgN
Distance moved by the body after applying force = hm
Work done in lifting the body from a to B distance = Force × Distance
Energy cannot be destroyed, hence, this energy is stored as potential energy in the stone.
m = 10Kg
g = 10 m/s²
h = 10 m
PE = mgh
PE = mgh
= 10 × 10 × 10
= 1000Joules

09. Short & Long Answer Questions- Gravitation

February 17, 2026 by khushikhanera

Short Answer Type Questions

Q1: What is the S.I. unit of thrust?
Ans: Newton.

Q2: What is the S.I. unit of pressure?
Ans: The S.I. unit of pressure = N/m² = Pascal.

Q3: Define thrust.
Ans: The net force exerted by a body in a particular direction is called thrust.

Q4: Define pressure.
Ans: The force exerted per unit area is called pressure.

Q5: Why is it easier to swim in seawater than in river water?
Ans: The density of seawater is more due to dissolved salts in it as compared to the density of river water. Hence the buoyant force exerted on the swimmer by the sea water is more which helps in floating and makes swimming easier.

Q6: Why a truck or a motorbike has much wider tyres?
Ans: The pressure exerted by it can be distributed to more area, and avoid the wear and tear of tyres.

Q7: Why are knives sharp?
Ans: To increase the pressure, area is reduced,
As pressure ∝ 1/Area hence the pressure or force exerted on a body increases.

Q8: Why is the wall of dam reservoir thicker at the bottom?
Ans: The pressure of water in dams at the bottom is more, to withstand this pressure the dams have wider walls.

Q9: Why do nails have pointed tips?
Ans: The force exerted when acts on a smaller area, it exerts larger pressure. So the nails have pointed tips.

Q10: While swimming why do we feel light?
Ans: The swimmer is exerted by an upward force by water, this phenomenon is called buoyancy and it makes the swimmer feel light.

Q11: Define density and give its unit.
Ans: The density of a substance is defined as mass per unit volume. Its unit is kg/m³.

Q12: What is relative density?
Ans: The relative density of a substance is the ratio of its density to that of water.
Relative density = density of a substance/density of water

Short Answer Type Questions
Q1: A ship made of iron does not sink but the iron rod sinks in water, why?
Ans: The iron rod sinks due to high density and less buoyant force exerted by the water on it, but in case of ship the surface area is increased, the upthrust experienced by the body is greater. So it floats on water.

Q2: Camels can walk easily on desert sand but we are not comfortable walking on the sand. State reason.
Ans: Camels feet are broad and the larger area of the feet reduces the force/ pressure exerted by the body on the sand. But when we have to walk on the same sand, we sink because the pressure exerted by our body is not distributed but is directional.

Q3: What is lactometer and hydrometer?
Ans: Lactometer is a device used to find the purity of a given sample of milk. Hydrometer is a device used to find the density of liquids.

Q4: The relative density of silver is 10.8. What does this mean?
Ans: It means that the density of silver is 10.8 times more than that of water.

Q5: The relative density of gold is 19.3. The density of water is 10³ kg/m³? What is the density of gold in S.I. unit?
Ans: Relative density of gold = 19.3
Relative density of gold = Density of gold/Density of water
∴ Density of gold = Relative density of gold x Density of water
= 19.3 x 10³ Kg/m³
=19300 Kg/m³

Q6: State Archimedes’ principle.
Ans: Archimedes’ principle—When a body is immersed fully or partially in a fluid, it experiences an upward force that is equal to the weight of the fluid displaced by it.
It is used in designing of ships and submarines.

Q7: Two cork pieces of same size and mass are dipped in two beakers containing water and oil. One cork floats on water but another sinks in oil. Why?
Ans The cork floats on water because the density of cork is less than the density of water, and another cork sinks in the oil because the density of cork is more than the oil.

Q8: What are fluids? Why is Archimedes’ principle applicable only for fluids? Give the application of Archimedes’ principle.
Ans: Fluids are the substances which can flow e.g., gases and liquids are fluids. Archimedes’ principle is based on the upward force exerted by fluids on any object immersed in the fluid.
Hence it is applicable only for fluids.
Applications of Archimedes’ principle:
1. It is used in designing ships and submarines.
2. It is used in designing a lactometer, used to determine the purity of milk.
3. To make hydrometers, used to determine the density of liquids.

Long Answer Type Questions

Q1: With the help of an activity prove that the force acting on a smaller area exerts a larger pressure.
Ans: Consider a block of wood kept on a tabletop. The mass of the wooden block is 5 kg. Its dimension is 40 cm x 20 cm x 10 cm.
Now, we have to find the pressure exerted by the wooden block on the tabletop by keeping it vertically and horizontally.
The mass of the wooden block = 5 kg
The weight of the wooden block applies a thrust on the tabletop
∴ Thrust = F = m * g
= 5 kg * 9.8 m/s² = 49 N
( case a ) — when the wooden box is kept vertically with sides 20 cm * 10 cm.
Area of a side = length * breadth
= 20 cm * 10 cm
= 200 cm² = 0.02 m²

(case b) — When the block is kept horizontally with side 40 cm * 20 cm
Area = length * breadth
= 40 cm * 20 cm
= 800 cm² = 0.08 m²

∴ The pressure exerted by the box in case (a) is more as compared to the pressure exerted in case (b).The area is reduced and the pressure exerted is more.
This shows that pressure ∝ 1/area.
Pressure will be larger if the area is reduced.
Application:
• Nails have pointed tips.
• Knives have sharp edges.
• Needles have pointed tips.

Activity-Based Questions

Q1: • Take an empty plastic bottle. Close the mouth of the bottle with an airtight stopper. Put it in a bucket filled with water. You see that the bottle floats.
• Push the bottle into the water. You feel an upward push. Try to push it further down. You will find it difficult to push deeper and deeper. This indicates that water exerts a force on the bottle in the upward direction. The upward force exerted by the water goes on increasing as the bottle is pushed deeper till it is completely immersed.
• Now, release the bottle. It bounces back to the surface.
• Does the force due to the gravitational attraction of the earth act on this bottle? If so, why doesn’t the bottle stay immersed in water after it is released? How can you immerse the bottle in water?
Ans: Yes, the bottle is attracted downwards by the earth’s gravitational force. On pushing the bottle with force in the water it does not remain there but comes up because of the upward force exerted by water on the bottle. This upward force is called upthrust or buoyant force. When the upward force or buoyant force is greater than the downward force ‘g’ the bottle will float. But if downward force is greater than upward force, the bottle will sink. The upward force (buoyant force) acting on the bottle can be reduced by increasing the force on the bottle or by filling the bottle with sand, water, etc.

Q2:• Take a beaker filled with water.
• Take an iron nail and place it on the surface of the water.
• Observe what happens.
Ans: The iron nail sinks as the density of nail is more and the downward force exerted on nail is more than the buoyant force.

Q3: • Take a beaker filled with water.
• Take a piece of cork and an iron nail of equal mass.
• Place them on the surface of the water.
• Observe what happens.
Ans: The iron nail sinks as the density of nail is more and the downward force exerted on nail is more than the buoyant force. The cork floats as the density of cork is less and the buoyant force exerted on it is more than the downward force.

Q4: • Take a piece of stone and tie it to one end of a rubber string or a spring balance.
• Suspend the stone by holding the balance or the string as shown in figure (a).

• Note the elongation of the string or the reading on the spring balance due to the weight of the stone.
• Now, slowly dip the stone in the water in a container as shown in Fig. (b).
• Observe what happens to the elongation of the string or the reading on the balance.
Observations :
• In Fig. (a) the elongation of the string is 6 cm.
• In Fig. (b) when the stone is dipped in water the length of the string is reduced to 5 cm.
• The length of the string in case (b) decreases due to the upward force exerted by water on the stone called buoyant force.

Value-Based Questions

Q 1: A milkman sold his milk in the city and always carried a lactometer with him. The customers trusted him and his business flourished.
(a) What is a lactometer?
(b) What is the principle of working of a lactometer?
(c) What value of milkman is seen in this case?
Ans:

(a) A lactometer is an instrument used to measure the purity of milk. It helps determine the specific gravity of milk, which can indicate whether it has been diluted with water or not.

(b) The principle of working of the lactometer is based on Archimedes’ Principle. The lactometer floats in milk, and the level at which it floats depends on the density or specific gravity of the milk. If the milk is pure, the lactometer will float at a certain level. If the milk is diluted with water, the specific gravity decreases, and the lactometer will float higher in the liquid.

(c) The value of the milkman reflected in this case is honesty and integrity. He uses the lactometer to ensure that the milk he sells is pure, earning the trust of his customers and helping his business grow.

Q 2: Reeta was wearing a high heel shoes for a beach party, her friend told her to wear flat shoes as she will be tired soon with high heels and would not feel comfortable,
(a) Why would one feel tired with high-heeled shoes on the beach?
(b) Give the unit of pressure.
(c) What value of Reeta’s friend is seen in the above act?
Ans:

(a) One would feel tired with high-heeled shoes on the beach because high heels concentrate the weight on a small area of the feet. On a soft surface like sand, the high heel does not distribute the body weight evenly, leading to more pressure on the feet. This makes it harder to walk and causes discomfort and fatigue.

(b) The unit of pressure is the Pascal (Pa). It is defined as one newton per square meter (N/m²).

(c) The value of Reeta’s friend reflected in this case is concern and care. Her friend is looking out for Reeta’s comfort and well-being by advising her to wear flat shoes that would be more suitable for walking on the beach, helping to avoid unnecessary discomfort.

Q 3: In the school fair, there was a game in which one need to find the heaviest ball without holding them in hand. Three balls were given and few disposable glasses were kept. Tarun saw his friend struggling to win the game but he was unable to find the heaviest ball. Tarun helped him by dipping the three balls one by one in the glasses full of water upto the brim and finally they won the game.
(a) Why did Tarun told his friend to dip the balls one by one in completely filled glass of water?
(b) Name the principle used here.
(c) What value of Tarun is reflected in this case?
Ans:

(a) Tarun told his friend to dip the balls one by one in completely filled glasses of water because the heaviest ball would displace more water due to its greater volume. The one that displaces the most water is the heaviest.

(b) The principle used here is Archimedes’ Principle, which states that the upward buoyant force exerted on a body submerged in a fluid is equal to the weight of the fluid displaced by the body.

(c) The value of Tarun reflected in this case is helpfulness and problem-solving ability. He used his knowledge to assist his friend and help them win the game.

08. Short & Long Answer Questions (part- 2)- Force and Laws of Motion

February 17, 2026 by khushikhanera

Long Answer Type Questions

Ques 1: Explain Newton’s second law of motion and with the-help of an example show how it is used in sports.

Ans: Newton’s second law of motion: The rate of change of momentum of an object is proportional to the applied unbalanced force in the direction of the force.

Let us assume:

Object of mass m, is moving along a straight line with an initial velocity ‘u’, It is uniformly accelerated to velocity v in time ‘t by the application of force,

F throughout the time ‘t’.

Initial momentum of the object = p₁ = mu

Final momentum of the object = p₂ = mv

The change in momentum ∝ p₂-p₁

∝ mv-mu

= m (v-u)

The rate of change of momentum ∝

∴ Applied force F ∝

K = constant of proportionality

F = kg m/s² = Newton

Use of second law of motion in sports :

In cricket field, the fielder gradually pulls his hands backward while catching a ball. The fielder catches the ball and gives swing to his hand to increase the time during which the high velocity of the moving ball decreases to zero.The acceleration of the ball is decreased and therefore the impact of catching the fast moving balls reduced.

If not done so, then the fast moving ball will exert large force and may hurt the fielder.

Ques 2: State all 3 Newton’s law of motion. Explain inertia and momentum.

Ans: Newton’s I law of motion: An object remains in a state of rest or of uniform motion in a straight line unless acted upon by an external unbalanced force.

Newton’s II law of motion: The rate of change of momentum of an object is proportional to the applied unbalanced force in the direction of the-force.

Newton’s III law of motion: To every action, there is an equal and opposite reaction and they act on two different bodies.

Inertia: The natural tendency of an object to resist a change in their state of rest or of uniform motion is called inertia.

Momentum: The momentum of an object is the product of its mass and velocity and has the same direction as that of the velocity. Its S.I. unit is kgm/s. p = m x v

Ques 3: Define force. Give its unit and define it. What are different types forces?

Ans: Force: It is a push or pull on an object that produces acceleration in the body on which it acts.

A force can do 3 things on a body

(a) It can change the speed of a body.

(b) It can change the direction of motion of a body.

The S.I. unit of force is Newton.

Newton: A force of one Newton produces an acceleration of 1 m/s² on an object of mass 1 kg.

1N = 1kg m/s²

Types of forces:

(i) Balanced force: When the forces acting on a body from the opposite direction do not change the state of rest or of motion of an object, such forces are called balanced forces.

(ii)Unbalanced force: When two opposite forces acting on a body move a body in the direction of the greater force or change the state of rest, such forces are called as unbalanced force.

(ii)Frictional force: The force that always opposes the motion of object is called force of friction.

Ques 4: What is inertia? Explain different types of inertia. Give 3 examples in daily life which shows inertia.

Ans: Inertia: The natural tendency of an object to resist change in their state of rest or of motion is called inertia.

The mass of an object is a measure of its inertia. Its S.I. unit is kg.

Types of inertia:

Inertia of rest: The object at rest will continue to remain at rest unless acted upon by an external unbalanced force.

Inertia of motion: The object in the state of uniform motion will continue to remain in motion with same speed and direction unless it is acted upon by an external unbalanced force. .

Three examples of inertia in daily life are:

1. When we are travelling in a vehicle and sudden brakes are .applied we tend to fall forward.

2. When we shake the branch of a tree vigorously, leaves fall down.

3. If we want to remove the dust from carpet we beat the carpet so that dust fall down.

Activity-based Questions

Also read: Previous Year Questions Answers – Force and Laws of Motion

Ques 1: • Make a pile of similar carom coins on a table, as shown in the figure.

• Attempt a sharp horizontal hit at the bottom of the pile using another carom coin or striker. If the hit is strong enough the bottom coin moves out quickly. Once the lowest coin is removed, the inertia of the other coins makes them ‘fall’ vertically on the table.

Inertia: It is the tendency of a body to maintain its state of rest or of motion.

Ques 2: • Set a five-rupees coin on a stiff card covering an empty glass tumbler standing on a table as shown in the figure.

• Give the card a sharp horizontal flick with a finger. If we do it fast then the card shoots away, allowing the coin to fall vertically into the glass tumbler due to its inertia.

• The inertia of the coin tries to maintain its state of rest even when the card flows off.

Ans: The force applied on the card due to flicking changes the inertia of the card but the coin resist a change and stay at the rest i.e. inertia of rest and due to gravity falls down in the tumbler.

Ques 3: Place a water-filled tumbler on a tray.

• Hold the tray and turn around as fast as you can.

• We observe that the water spills. Why?

Ans: The water-filled in tumbler and tray are at rest. On moving/turning around the tray at faster speed the water spills because the tray and the tumbler comes into motion while the water in the tumbler remain at inertia of rest.

Ques 4:• Request two children to stand on two separate carts as shown on the next page.

• Give them a bag full of sand or some other heavy object. Ask them to play a game of catch with the bag.

• Does each of them receive an instantaneous reaction as a result of throwing the sand bag (action)?

• You can paint a white line on cartwheels to observe the motion of the two carts when the children throw the bag towards each other.

Ans: Yes, in this case each of them receives an instantaneous reaction as a result of throwing the sand bag.

This activity explain Newton’s III law of motion i.e., the force is exerted forward in throwing the bag full of sand and the person who is throwing it gets pushed backward.

Ques 5: • Take a big rubber balloon and inflate it fully. Tie its neck using a thread. Also using adhesive tape, fix a straw on the surface of this balloon.
• Pass a thread through the straw and hold one end of the thread in your hand or fix it on the wall.
• Ask your friend to hold the other end of the thread or fix it on a wall at some distance. The arrangement is shown in the figure below.
• Now remove the thread tied on the neck of balloon. Let the air escape from the mouth of the balloon.
• Observe the direction in which the straw moves.Observation:
When the air escapes out from the balloon the straw moves in the opposite direction of the air moved out of the balloon.
This activity explains the law of conservation of momentum and Newton’s III law of motion.
Initial momentum = Final momentum

Ques 6: • Take a test tube of good quality glass material and put a small amount of water in it. Place a stop cork at the mouth of it.
• Now suspend the test tube horizontally by two strings or wires as shown in the figure on next page.
• Heat the test tube with a burner until water vaporises and the cork blows out.
• Observe that the test tube recoils in the direction opposite to the direction of the cork.

Observation:
The cork is pushed out in forward direction by the hot steam. The test tube is pushed in the backward direction.
It explain Newton’s III law of motion and conservation of momentum.

Value-based Questions

Ques 1: Class V students were playing cricket with the cork hall in the school campus. Charu a senior student told them about the accidents that can occur due to cork ball in the campus and also advised them to bring soft cosco ball to play the game.

(a) Why it was safe to play with soft ball and not with hard cork ball?

(b) A player pulls his hands backwards after holding the ball shot at high speed. Why?

(c) What value of Charu is seen in this act?

Ans: (a) The soft ball will have less inertia as compared to the heavy ball and it would not hurt the players.

(b) By pulling the hand backwards it reduces the force exerted by the ball on hands.

Ques 2: Saksham saw his karate expert friend breaking a slate. He tried to break the slate but Saksham’s friend stopped him from doing so and told him that it would hurt, one needs lot of practice in doing so.

(a) How can a karate expert break the slate without any injury to his hand?

(b) What is Newton’s third law of motion?

(c) What value of Saksham’s friend, is seen in the above case?

Ans: (a) A karate player applies the blow with large velocity in a very short interval of time on the slate, therefore large force is exerted on the slate and it breaks.

(b) To every action there is an equal and opposite reaction, both act on different bodies.

Saksham’s friend showed the value of being responsible and caring friend.

08. Short & Long Answer Questions (part- 1)- Force and Laws of Motion

February 17, 2026 by khushikhanera

Ques 1: Define force.
Ans: It is a push or pull on an object that produces acceleration in the body on which it acts.

Ques 2: What is the S.I. unit of force?
Ans: The S.I. unit of force is Newton.

Ques 3: Define one Newton.
Ans: A force of one Newton produces an acceleration of 1 m/s² on an object of mass 1 kg.
1 N = 1 kg m/s²

Ques 4: What is balanced force?
Ans: When forces acting on a body from the opposite direction do not change the state of rest or of motion of an object, such forces are called balanced forces.

Ques 5: What is frictional force?
Ans: The force that always opposes the motion of an object is called the force of friction.

Ques 6: What is inertia?
Ans: The natural tendency of an object to resist a change in its state of rest or of uniform motion is called inertia.

Ques 7: State Newton’s first law of motion.
Ans: An object remains in a state of rest or of uniform motion in a straight line unless acted upon by an external unbalanced force.

Ques 8: State Newton’s second law of motion.
Ans: The rate of change of momentum of an object is proportional to the applied unbalanced force in the direction of the force.

Ques 9: What is momentum?
Ans: The momentum of an object is the product of its mass and velocity and has the same direction as that of the velocity. The S.I. unit is kg m/s. (p = mv)

Ques 10: State Newton’s III law of motion.
Ans: For every action, there is an equal and opposite reaction, and they act on two different bodies.

Ques 11: Which will have more inertia, a body of mass of 10 kg or a body of mass of 20 kg?
Ans: A body of mass 20 kg will have more inertia.

Ques 12: Name the factor on which the inertia of the body depends.
Ans: The inertia of a body depends upon the mass of the body.

Ques 13: Name two factors that determine the momentum of a body.
Ans: Two factors on which the momentum of a body depends are mass and velocity. Momentum is directly proportional to the mass and velocity of the body.

Ques 14: What decides the rate of change of momentum of an object?
Ans: The rate of change of momentum of an object is proportional to the applied unbalanced force in the direction of force.

Ques 15: The diagram shows a moving truck. Forces A, B,
C and D are acting on the truck.
Name the type of forces acting on a truck.

Ans: The forces A, B, C and D acting on the truck are:
A → driving force
B → reacting force
C → frictional force
D → weight/gravitational force

Short Answer Type Questions

Ques 1: State the difference between balanced and unbalanced force.
Ans:

Balanced force	Unbalanced force
Forces acting on a body from opposite directions are the same.	Forces acting on a body from two opposite directions are not the same.
It does not change the state of rest or motion of an object.	It does change the state of rest or of motion of an object.

Ques 2: What change will force bring in a body?
Ans: Force can bring the following changes in the body:
It can change the speed of a body.
It can change the direction of motion of a body,
It can change the shape of the body.

Ques 3: When a motorcar makes a sharp turn at a high speed, we tend to get thrown to one side. Explain why?
Ans: It is due to the law of inertia. When we are sitting in a car moving in a straight line, we tend to continue in our straight-line motion. But when the engine applies an unbalanced force to change the direction of motion of the motorcar. We slip to one side of the seat due to the inertia of our bodies.

Ques 4: Explain why it is dangerous to jump out of a moving bus.
Ans: While moving in a bus, our body is in motion. On jumping out of a moving bus, our feet touched the ground and came to rest. The upper part of our body stays in motion and moves forward due to the inertia of motion, and hence, we can fall in the forward direction.
Hence, to avoid this, we need to run forward in the direction of the bus.

Ques 5: Why do fielders pull their hands gradually with the moving ball while holding a catch?
Ans: While catching a fast-moving cricket ball, a fielder on the ground gradually pulls his hands backward with the moving ball. This is done so that the fielder increases the time during which the high velocity of the moving ball decreases to zero. Thus, the acceleration of the ball is decreased, and therefore, the impact of catching the fast-moving ball is reduced.

Ques 6: In a high jump athletic event, why are athletes made to fall either on a cushioned bed or on a sand bed?
Ans: In a high jump athletic event, athletes are made to fall either on a cushioned bed or on a sand bed so as to increase the time of the athlete’s fall to stop after making the jump. This decreases the rate of change of momentum and, hence, the force.

Ques 7: How does a karate player break a slab of ice with a single blow?
Ans: A karate player applied the blow with large velocity in a very short interval of time on the ice slab, which therefore exerted a large amount of force on it and suddenly broke the ice slab.

Ques 8. Why are roads on mountains inclined inwards at turns?
Ans: A vehicle moving on mountains is in the inertia of motion. At a sudden turn, there is a tendency for the vehicle to fall off the road due to a sudden change in the line of motion; hence, the roads are inclined inwards so that the vehicle does not fall down the mountain.

Ques 9: For an athletic race, why do athletes have a special posture with their right foot resting on a solid supporter?
Ans: Athletes have to run the heats, and they rest their feet on solid supports before the start so that during the start of the race, the athlete pushes the support with a lot of force and this support gives him equal and opposite push to start the race and get a good start to compete for the race.

Ques 10: Why do you think it is necessary to fasten your seat belts while traveling in your vehicle?
Or
How are safety belts helpful in preventing any accidents?
Ans: While we are traveling in a moving car, our body remains in a state of rest with respect to the seat. But when the driver applies sudden breaks or stops the car, our body tends to continue in the same state of motion because of its inertia. Therefore, this sudden break may cause injury to us by impact or collision. Hence, the safety belt exerts a force on our body to make the forward motion slower.

Ques 11: When you kick a football, it flies away, but when you kick a stone, you get hu why?
Ans: This is because stone is heavier than football, and heavier objects offer larger inertia.
When we kick a football, its mass is less, and inertia is also less, so the force applied by our kick acts on it, and hence, it shows larger displacement, but in the case of stone, it has a larger mass and offers larger inertia. When we kick (action) the stone, it exerts an equal and opposite force (reaction), and hence it hurts the foot.

Ques 12: If a person jumps from a height on a concrete surface, he gets hurt. Explain.
Ans: When a person jumps from a height, he is in a state of inertia of motion. When he suddenly touches the ground, he comes to rest in a very short time, and hence, the force exerted on his body by the hard concrete surface is very high, and the person gets hurt.

Ques 13: What is the relation between Newton’s three laws of motion?
Ans: Newton’s first law explains the unbalanced force required to bring change in the position of the body.
The second law states/explains the amount of force required to produce a given acceleration.
And Newton’s third law explains how these forces acting on a body are interrelated.

Ques 14: Give any three examples in daily life that are based on Newton’s third law of motion.
Ans: Three examples based on Newton’s third law are :
(i) Swimming: We push the water backward to move forward.
action – water is pushed behind
reaction – water pushes the swimmer ahead
(ii) Firing gun: A bullet is fired from a gun and the gun recoils.
action – gun exerts a force on the bullet
reaction – bullet exerts an equal and opposite force on the gun
(ii) Launching of rocket: action – hot gases from the rocket are released. Reaction – the gases exert an upward push on the rocket

Ques 15: A bullet of m.ass 20 g is horizontally fired with a velocity of 150 m/s from a pistol of mass 2 kg. What is the
recoil velocity of the pistol?
Ans:

Total momentum of the pistol and bullet before firing, when the gun is at rest
= m₁u₁ + m₂u₂
= (0.02 * 0) + (2 * 0)
0 kg m/s
Total momentum of the pistol and bullet after it is fired
= m₁v₁ + m₂v₂
= (0.02 kg * 150) + (2 kg * v)
= 3+ 2v
∴ Total momentum after firing = Total momentum before firing
3 + 2v
∴ v = -3/2 = -1.5 m/s

07. Short & Long Answer Questions- Motion

February 17, 2026 by khushikhanera

Very Short Answer Questions

Ques 1: The phenomenon of motion was placed on a sound scientific footing by two scientists. Write their names.
Ans: Galileo Galilei and Isaac Newton. Galileo laid the experimental foundations of kinematics and Newton formulated the laws of motion that provided a systematic explanation of how and why bodies move.
Ques 2: Are rest and motion absolute or relative terms?
Ans: They are relative terms. Whether an object is at rest or in motion depends on the chosen reference point or frame of reference.
Ques 3: Suppose a ball is thrown vertically upwards from a position P above the ground. It rises to the highest point Q and returns to the same point P. What is the net displacement and distance travelled by the ball?
Ans: Displacement is zero because the initial and final positions are the same. Distance travelled is twice the separation between P and Q, since the ball goes from P to Q and then back from Q to P.
Ques 4: Which speed is greater: 30 m/s or 30 km/h?
Ans: 30 m/s. (30 km/h = 30 × 1000/3600 m/s = 8.33 m/s, which is much less than 30 m/s.)
Ques 5: What do you mean by 2 m/s²?
Ans: It means the velocity of the body increases by 2 m/s every second. If the acceleration is negative, the speed would decrease by 2 m/s every second.
Ques 6: Can uniform linear motion be accelerated?
Ans: No. Uniform linear motion means constant velocity, so the acceleration is zero. Any non-zero acceleration changes the velocity and therefore the motion is not uniform.
Ques 7: Define one radian.
Ans: One radian is the angle subtended at the centre of a circle by an arc whose length is equal to the radius of the circle. (One radian ≈ 57.3°.)
Ques 8: What is the relation between linear velocity and angular velocity
Ans: Linear velocity = Angular velocity × Radius of the circular path. (v = ω × r)

Short Answer Questions

Ques 1: Give an example of a body that may appear to be moving for one person and stationary for the other.

Ans: Passengers in a moving bus see trees, buildings and people on the roadside appearing to move backward, while a person standing on the roadside sees the bus and its passengers moving forward. At the same time, each passenger may see fellow passengers sitting beside them as stationary. This illustrates that motion is relative and depends on the observer’s reference frame.

Ques 2: How can we describe the location of an object?

Ans: To describe the position of an object we specify a reference point called the origin and, when needed, a reference direction. For example, saying a library is 2 km north of the railway station locates the library with respect to the railway station, which acts as the reference point.

Ques 3: What do you mean by average speed? What are its units?

Ans: Average speed is the total distance travelled divided by the total time taken. If a body covers total distance D in time t, average speed = D/t. The SI unit is metre per second (m s^-1).

Ques 4: What is the difference between uniform velocity and non-uniform velocity?

Ans: Uniform velocity: An object has uniform velocity when it covers equal distances in equal intervals of time in a specified direction; its speed and direction are constant. Example: a car moving at 40 km h^-1 towards west with no change in speed or direction.

Non-uniform velocity: An object has non-uniform velocity if it covers unequal distances in equal time intervals or if its direction changes. Example: the blades of a revolving fan move at constant speed but their velocity is non-uniform because the direction keeps changing.

Ques 5: Differentiate between distance and displacement.

Ans:

Ques 6: What are the uses of a distance-time graph?
Ans: The uses of a distance-time graph are:
(a) It shows the position of the body at any instant of time.
(b) From the graph we can read the distance covered by the body during a chosen time interval.
(c) The slope of the distance-time graph gives the speed of the body at any instant, so the graph gives information about how the speed changes with time.

Long Answer Questions

Ques 1: With the help of a graph, derive the relation v = u + at.
Ans:

Consider the velocity-time graph of an object that moves under uniform acceleration as shown in the figure (u≠0).

From this graph, we can see that initial velocity of the object (at point D) is u and then it increases to v (at point B) in time t. The velocity changes at uniform rate a. As shown in the figure, the lines BC and BE are drawn from point B on the time and the velocity axes respectively.
The initial velocity is represented by OD.
The final velocity is represented by BE.
The time interval t is represented by OE.
BA = BE – EA, represents the change in velocity in time interval t.
If we draw DA parallel to OE, we observe that BE = BA + DE = BA + OD
Substituting, BE with v and OD with u, we get
v = BA + u
or, BA = v – u — (i)
Thus, from the given velocity-time graph, the acceleration of the object is given by Change in velocity
a = (Change in velocity)/(Time Taken)= BA/DA= BA/OE
Substituting OC with t, we get
a = BA/t ⇒ BA = at — (ii2)
From equations (1) and (2), we have
v-u = at or v =u + at

Ques 2: Obtain a relation for the distance travelled by an object moving with a uniform acceleration in the interval between 4th and 5th seconds.
Ans: Use the equation of motion for distance from rest with initial velocity u and constant acceleration a:
s(t) = u × t + 1/2 × a × t².
Distance travelled in first 5 s, s(5) = u × 5 + 1/2 × a × 5² = 5u + 25/2 a.
Distance travelled in first 4 s, s(4) = u × 4 + 1/2 × a × 4² = 4u + 8a.
Distance covered during the interval between 4th and 5th seconds = s(5) – s(4)
= (5u + 25/2 a) – (4u + 8a)
= u + (25/2 – 16/2) a
= u + 9/2 a.
Thus the distance travelled in the fifth second is u + 9/2 a (metres, if u in m s^-1 and a in m s^-2).

06. Short & Long Answer Questions- Tissues

February 17, 2026 by khushikhanera

Q1. Name the tissues responsible for the movement of the body.

Ans: Muscle tissue and nervous tissue are the primary tissues responsible for body movement.

Muscle tissueis divided into three types:
- Striated muscle (voluntary muscles that we control, like those in our limbs)
- Smooth muscle (involuntary muscles found in organs)
- Cardiac muscle (the muscle of the heart)
Nervous tissue consists of neurons that transmit signals rapidly throughout the body.
Neurons allow us to control muscle movement by sending nerve impulses.

The combination of muscle and nervous tissue is essential for coordinated movement and response to stimuli.

Q2. What does a neuron look like?

Ans: A neuron is the basic unit of nervous tissue. It has a unique structure comprising:

Cell body: Contains the nucleus and cytoplasm.
Axon: A long, thread-like part that transmits signals.
Dendrites: Short, branched parts that receive signals from other neurons.

Neurons can be quite long, with some measuring up to a metre. They are bundled together by connective tissue to form nerves. The signals that travel along these fibres are known as nerve impulses, which enable muscle movement and rapid responses to stimuli.

Q3. Name the types of simple tissues.

Ans: The types of simple tissues in plants are:

Parenchyma
Collenchyma
Sclerenchyma

Q4. Name the types of complex tissues.

Ans: Complex tissues in plants consist of more than one type of cell that work together to perform a specific function. The main types of complex tissues are:

Xylem – Responsible for transporting water and minerals from the roots to other parts of the plant.
Phloem – Transports food produced in the leaves to other areas of the plant.

Both xylem and phloem are part of the vascular bundle, which is essential for the plant’s nutrient and water transport system.

Q5. Where is apical meristem found?

Ans: Apical meristem is found at the growing tips of stems and roots. It plays a crucial role in:

Increasing the length of the stem.
Increasing the length of the root.

Additionally, the lateral meristem (cambium) is responsible for increasing the girth of stems and roots, while the intercalary meristem is located near the nodes in some plants.

Q6. Which tissue makes up the husk of coconut?

Ans: The husk of a coconut is primarily made up of sclerenchyma tissue.

This tissue has the following characteristics:

It consists of dead cells that provide strength.
The cells are long and narrow with thickened walls due to lignin.
These thick walls often leave no internal space within the cells.
Sclerenchyma is also found in stems, around vascular bundles, and in the hard coverings of seeds and nuts.

Overall, this tissue plays a crucial role in providing support to various plant parts.

Q7. What are the constituents of phloem?

Ans: The phloem is made up of several important cell types:

Sieve tubes: These are tubular cells with perforated walls that facilitate the transport of food.
Companion cells: These cells support sieve tubes and help in the transport process.
Phloem parenchyma: This type of cell stores food and assists in transport.
Phloem fibres: These provide structural support to the phloem.

All phloem cells, except for phloem fibres, are living cells, playing a crucial role in moving nutrients from the leaves to other parts of the plant.

Q8. Define aerenchyma.

Ans: Aerenchyma is a type of parenchyma tissue that contains large air-filled cavities.

This tissue is particularly important for aquatic plants, as it:

Facilitates floating in water.
Helps in the exchange of gases.

In some cases, aerenchyma can also contain chlorophyll, allowing it to perform photosynthesis, and is then referred to as chlorenchyma.

Q9. What is the utility of tissues in multicellular organisms?

Ans: Tissues play a crucial role in multicellular organisms by:

Facilitating growth and development of organs.
Enabling the organisation of different organ systems.
Allowing cells to perform specific functions efficiently.

In summary, tissues are essential for the proper functioning and coordination of various biological processes in complex organisms.

Q10. Name the two types of tissues.

Ans: Types of Tissues

Plant Tissues

Divided into two main types: meristematic and permanent.
Meristematic tissue is found in growing areas and is capable of division.
Permanents tissuesarise from meristematic tissue and are classified into:
- Simple tissues:
  - Parenchyma
  - Collenchyma
  - Sclerenchyma
- Complex tissues:
  - Xylem
  - Phloem

Animal Tissues

Includes four main types:
- Epithelial (e.g., squamous, cuboidal, columnar)
- Connective (e.g., areolar, adipose, bone)
- Muscular (e.g., striated, unstriated, cardiac)
- Nervous (made of neurons)

Q11. Name the two types of plant tissue.

Ans: Plant tissues are classified into two main types:

Meristematic tissue: This is the dividing tissue found in the growing regions of plants.
Permanant tissue: This tissue forms when meristematic tissue loses its ability to divide. It is further classified into:
- Simple tissues: Includes parenchyma, collenchyma, and sclerenchyma.
- Complex tissues: Includes xylem and phloem.

Q12. What is differentiation?

Ans: The process by which cells acquire a specific shape, size, and function is known as differentiation. This occurs when:

Cells formed from meristematic tissue lose their ability to divide.
They take on distinct roles, leading to the formation of permanent tissues.

Differentiation is essential for the development of various types of tissues in plants and animals, allowing for the specialisation of cells to perform specific functions efficiently.

Q13. Name the three types of meristematic tissues.

Ans: The three types of meristematic tissues are:

Apical meristem – Located at the tips of roots and shoots.
Lateral meristem – Found along the sides of stems.
Intercalary meristem – Present at the nodes of plants.

Q14. Where is apical tissue found?

Ans: Apical tissue is found at the tips of:

Roots
Stems

This tissue is responsible for the growth in length of these plant parts.

Q15. What are tracheids?

Ans: Tracheids are specialised cells found in the xylem of plants. They have the following characteristics:

They are elongated with tapering ends.
Tracheids have thick walls, which provide structural support.
Many tracheids are dead cells when mature, allowing for efficient water transport.
They are tubular structures that facilitate the movement of water and minerals vertically within the plant.

Q16. What are guard cells?

Ans: Guard cells are specialised cells that surround each stoma, which are small pores found on the surface of leaves.

They have a kidney shape and play a crucial role in regulating gas exchange.
Guard cells control the opening and closing of stomata, allowing carbon dioxide in for photosynthesis and oxygen out.
They also help manage transpiration, which is the loss of water vapour from the plant.

Q17. Epithelial tissue is the simplest tissue. Write (F) for false or (T) for true.

Ans: True

Epithelial tissue is indeed the simplest type of tissue. Here are some key points:

It consists of a single layer of cells.
All cells in epithelial tissue are similar in structure.
This tissue serves as a protective barrier and is involved in absorption and secretion.

Q18. What are the functions of cuboidal epithelium?

Ans: The cuboidal epithelium serves several important functions:

Facilitates absorption of substances.
Involved in excretion processes.
Plays a role in secretion of various substances.
Provides mechanical support to surrounding tissues.

Short Answer Type Questions

Q1. Give four differences between bone and cartilage.

Ans: Short Answer Type Questions

Q2. Give the functions of bone.

Ans: The functions of bone include:

Shape: It gives shape to the body.
Support: It provides skeletal support.
Muscle anchoring: It anchors the muscles.
Protection: It protects vital organs like the brain and lungs.

Q3. Give the functions of cartilage.

Ans: Functions of cartilage:

Support and flexibility for various body parts.
Smoothens surfaces at joints for easier movement.

Q4. Fill in the blanks:
(i) Water and minerals are conducted by ………………….
(ii) In higher plants food is conducted by ……………………..
(iii) Blood is a ……………. tissue.
(iv) Bone consists of………….cells.
(v) Cartilage consists of………………..cells.
(vi) Fibres are absent in………….type of connective tissue.
Ans: (i) Xylem
(ii) Phloem
(iii) Connective
(iv) Osteocyte
(v) Chondrocyte
(vi) Blood

Q5. What are the functions of areolar tissue?

Ans: Functions of areolar tissue:

Assists in the repair of tissues after an injury.
Helps in combating foreign toxins.
Anchors skin to the underlying muscles.

Q6. Name the tissues for the following: (a) Stores fat in an animal body. (b) Divides and re-divides to grow in plants. (c) Tissue that joins bone to bone. (d) Covers the external surface of an animal body.

Ans:

Adipose tissue – This tissue stores fat in the animal body.
Meristematic tissue – This tissue divides and re-divides to promote growth in plants.
Ligament – This tissue connects bone to bone.
Epithelial tissue – This tissue covers the external surface of an animal body.

Q7. What is stomata?

Ans: Stomata are tiny openings found on the surface of leaves. They play a crucial role in:

Gas exchange: Allowing oxygen and carbon dioxide to enter and exit the leaf.
Transpiration: Enabling the loss of water vapour from the plant.

Each stoma is surrounded by two guard cells, which regulate its opening and closing, ensuring that the plant maintains a balance between gas exchange and water loss.

Q8. Why does epidermal tissue have no intercellular space?

Ans: The epidermal tissue serves as a protective outer layer for plants, safeguarding their internal structures. It plays a crucial role in:

Preventing water loss
Shielding against mechanical injury
Defending against parasitic fungi

To effectively perform these protective functions, epidermal cells form a continuous layer without any intercellular spaces. This ensures that the tissue remains intact and functional.

Most epidermal cells are relatively flat, with thicker outer and side walls compared to the inner walls. In some plants, especially those in dry environments, the epidermis may be thicker to enhance water retention.

Additionally, small pores known as stomata are present in the epidermis, allowing for gas exchange and transpiration.

Q9. Name and give the function of each cell of the xylem.

Ans: Xylem consists of four main types of cells:

Tracheids and vessels: These cells transport water and minerals vertically throughout the plant.
Xylem parenchyma: This type stores food and aids in the lateral movement of water.
Xylem fibres: These cells provide support to the plant structure.

Q10. What is the function and location of stratified squamous epithelium?

Ans:

Stratified squamous epithelium is a type of tissue found primarily in the skin. Its main features include:

Composed of multiple layers of cells.
Designed to protect against wear and tear.
Also lines areas such as the oesophagus and the mouth.

This structure helps to prevent damage from physical abrasion and provides a barrier to external elements.

Q11. Give the difference between ligament and tendon.
Ans: Short Answer Type Questions

Q12. Give the difference between striated muscles and unstriated muscles.
Ans: Short Answer Type Questions

Q13. State the difference between bone and blood.
Ans: Short Answer Type Questions

Q14. Name all different types of tissues present in animals.

Ans:

There are four main types of tissues in animals:

Epithelial tissue: This tissue forms the outer and inner linings of the body, covering organs and cavities.
Muscular tissue: Composed of muscle cells, this tissue is responsible for movement.
Connective tissue: This type connects different organs and supports the body. Examples include blood, bone, and cartilage.
Nervous tissue: Made up of nerve cells, this tissue is essential for the nervous system and for transmitting impulses.

Q15. Why is blood called connective tissue?

Ans:

Blood is classified as a connective tissue due to its unique composition and functions:

It consists of cells suspended in a fluid called plasma.
The main components of blood include:
- Red blood cells (RBCs)
- White blood cells (WBCs)
- Platelets
Plasma serves as a medium that connects and transports various substances throughout the body, including:
- Oxygen
- Nutrients
- Hormones
- Waste products

This connective function is essential for maintaining the body’s overall health and facilitating communication between different organs.

Q16. Name three types of muscle tissues and give the function of each.

Ans:

Striated muscle:These muscles have alternating light and dark bands, known as striations. They are voluntary and primarily found in skeletal tissues, aiding in the movement of the body and bones.
Smooth muscle:These are involuntary muscles that control movements such as the passage of food in the alimentary canal and the contraction of blood vessels. They are located in the iris, uterus, and other organs.
Cardiac muscle:This type of muscle is found only in the heart. It is responsible for the rhythmic contraction and relaxation of the heart throughout life.

Q17. State the difference between simple tissues of plants.

Ans: The simple tissues of plants include:

Parenchyma: This is the most common type of simple tissue. It consists of living cells with thin walls, usually arranged loosely, allowing for large intercellular spaces. Parenchyma primarily stores food.
Collenchyma: This tissue provides flexibility and support to plants. It is found in leaf stalks just below the epidermis and consists of living cells that are elongated and thickened at the corners, with minimal intercellular space.
Sclerenchyma: This tissue makes plants hard and stiff. Composed of dead cells with thick lignified walls, sclerenchyma has very little internal space. It is commonly found in stems and the husk of coconuts.

Q18. With the help of a diagram show the difference between striated muscle fiber, smooth muscle fiber and cardiac muscle fiber.
Ans: Short Answer Type Questions

Q19. Name different types of meristematic tissue and draw a diagram to show their location.

Ans: The three types of meristematic tissue are:

Apical meristem – Responsible for growth in length, found at the tips of roots and stems.
Lateral meristem – Facilitates growth in thickness, located along the sides of stems and roots.
Intercalary meristem – Promotes growth in internodes, typically found near the nodes of some plants.

These tissues are crucial for the plant’s growth and development, as they produce new cells that eventually differentiate into various types of permanent tissues.

Meristematic Tissue

Q20. Explain the structure, function and location of nervous tissue.

Ans:

Structure: Nervous tissue is made up of cells known as neurons. Each neuron has:

A cell body containing a nucleus and cytoplasm.
A long, thin part called an axon.
Many short, branched parts known as dendrites.

Location: Nervous tissue is found in:

The brain
The spinal cord
Nerves throughout the body

Function: The primary roles of nervous tissue include:

Receiving and transmitting stimuli quickly within the body.
Facilitating movement by sending signals to muscles.
Enabling responses to various stimuli.

Long Answer Type Questions

Q1: Show the types of animal tissues using flow chart.
Ans:

Q2. What is connective tissue? Explain its types.

Ans: Connective tissue is a type of tissue that supports, binds, and connects other tissues and organs in the body. It consists of various cells embedded in a matrix, which can vary in consistency.

Blood: A fluid connective tissue that transports nutrients and oxygen.
Bone: A rigid connective tissue with a hard matrix made of calcium and phosphorus, providing structure and support.
Cartilage: A flexible connective tissue found in joints, the nose, and ears, with a matrix of proteins and sugars.
Tendons: Connect muscles to bones, made of strong fibrous tissue.
Ligaments: Connect bones to other bones, highly elastic and strong.
Adipose tissue: Stores fat and provides insulation.
Areolar tissue: A loose connective tissue that supports and binds other tissues.

The matrix of connective tissue varies depending on its function, ranging from jelly-like to dense or rigid. This diversity allows connective tissues to perform various roles in the body.

Q3. Describe the ‘epidermis’ in plants.

Ans: The epidermis is the outermost layer of a plant, consisting of a single layer of cells. It serves several important functions:

The epidermis protects the internal parts of the plant.
On aerial parts, it secretes a waxy, water-resistant layer that helps prevent water loss, mechanical injury, and invasion by parasitic fungi.
In leaves, small pores called stomata are present, which facilitate gas exchange (oxygen and carbon dioxide) and transpiration (water loss).
In roots, the epidermis has long hair-like structures that increase the surface area for water absorption.
In desert plants, the epidermis features a thick waxy coating of cutin, which acts as a waterproofing agent.

Q4. Explain the ‘complex tissue’ of plants.

Ans: Complex tissues in plants consist of more than one type of cell that work together to perform a specific function. The main types of complex tissues are:

Xylem: Responsible for transporting water and minerals.
Phloem: Transports food throughout the plant.

The components of xylem include:

Tracheids: Tubular structures that help in water transport.
Vessels: Also assist in transporting water.
Xylem parenchyma: Stores food and aids in lateral water movement.
Xylem fibres: Provide structural support.

The phloem consists of:

Sieve tubes: Tubular cells that transport food.
Companion cells: Support sieve tubes in their function.
Phloem fibres: Provide support.
Phloem parenchyma: Involved in storage and transport.

In summary, complex tissues like xylem and phloem are essential for the plant’s transportation and support systems.

Also read: Important Points to Remember & Revision Notes – Tissues

Activity-Based Questions

Q1: Take two glass jars and fill them with water.

Now, take two onion bulbs and place one on each jar, as shown in the figure given below.

Length	Day 1	Day 2	Day 3	Day 4	Day 5	Day 6	Day 7
Jar 1	3 cm	3.5 cm	4 cm	4.5 cm	5 cm	5.2 cm	5.4 cm
Jar 2	3 cm	3.5 cm	4 cm	4.5 cm	3.5 cm	3.5 cm	3.5 cm

• Observe the growth of roots in both the bulbs for a few days.
• Measure the length of roots on day 1, 2 and 3.
• On day 4, cut the root tips of the onion bulb in jar 2 by about 1cm. After this, observe the growth of roots in both the jars and measure their lengths each day for five more days and record the observations in tables, like the table
From the above observations, answer the following questions:
(a) Which of the two onions has longer roots? Why?
(b) Do the roots continue growing even after we have removed their tips?
(c) Why would tips stop growing in jar 2 after we cut them?
Answer: (a) The onion in jar 1 has longer roots, as the growth of roots continues in it due to intact root tips.
(b) The roots did not continue to grow in jar 2 after cutting down their tips. Activity-Based Questions (c) The tips of root stopped growing in jar 2 because the tips of these roots were cut down and the tissues which helps in the growth of roots i.e., meristematic tissues are removed from it.

Q2: Take a plant stem and with the help of your teacher cut into very thin slices or sections.
Now, stain the slices with safranin. Place one neatly cut section on a slide, and put a drop of glycerine.
Cover with a cover-slip and observe under a microscope. Observe the various types of cells and their arrangement.
Answer the following on the basis of your observations:
(a) Are all cells similar in structure?
(b) How many types of cells can be seen?
(c) Can we think of reasons why there would be so many types of cells?
Transverse section and Longitudinal section of stem
Answer:
(a) No, all cells are not similar in structure, we see variety of cells with different shape and size.
(b) We can see at least ten different types of cells in the slide.
(c) Yes, there are variety of cells so that each group of cell does a specific role in the overall growth of plant.

Q3: Take a freshly plucked leaf of Rheo.
Stretch and break it by applying pressure.
While breaking it, keep it stretched gently so that some peel or skin projects out from the cut.
Remove this peel and put it in a petridish filled with water.
Add a few drops of safranin.
Wait for a couple of minutes and then transfer it onto a slide. Gently place a cover slip over it.
Ans: (a) The slide shows epidermal cells with stomatal pores as shown in Fig. (a).
(b) On focusing stomata pores under microscope. We can see guard cells and stomata pore as shown in Fig. (b). Activity-Based Questions

Value-Based Questions

Q1: A group of students completed the project of finding the botanical names of all the trees present in the school campus. They prepared metal plates with names carved on it, to fix it on the plant trunks. Shreya was concerned that if the metal plate is fixed into tree many cells of the tree may get damaged. But the group members explained her that the outer layer of trunk does not have living cells and there won’t be any damage to the tree.
(a) What type of cells are present on the outer layer of the bark/tree trunk?
(b) How does the cprk act as a protective tissue?
(c) What value of the group is seen in the above cast?
Ans: (a) On the outer layer of the tree trunk/bark all thick layer of dead cells is present which acts as protective tissue.
(b) In cork, all cells are dead without intercellular spaces, the walls of the cells have deposition of suberin.
(c) The students in a group show team effort, peer learning and co-operatiye.

Q2: A paralytic patient was unable to walk. ‘The family member of the atient took the outmost care of the patient.
(a) Name two tissues responsible for the movement of a body.
(b) Name the tissues present in brain and spine.
(c) What value of the family members is seen in the above case?
Ans: (a) The two tissues responsible for movement of the body are muscular tissue and nervous tissue.
(b) The tissues present in brain and spine are nervous tissues.
(c) The family members showed the value of being caring, responsible, dutiful and kind.

05. Short and Long Answer Questions- The Fundamental Unit Of Life

February 17, 2026 by khushikhanera

Ques 1: What are plastids? Name the different types of plastids found in plant cell.
Ans: Plastids are organelles found only in plants. They are:
(a) Chloroplast-Containing chlorophyll
(b) Chromoplast-Containing carotenoids and xanthophyll (coloured plastids)
(c) Leucoplast-White or colourless plastids

Ques 2: What is plasma membrane made up of?
Ans: Plasma membrane is made up of proteins and lipids.

Ques 3: What did Robert Hooke observed first in cork cell?
Ans: Robert Hooke observed that cork consists of box like compartments which formed a honeycomb structure.

Ques 4: Name the autonomous organelles in the cell.
Ans: Chloroplasts and mitochondria are the autonomous organelles in the cells.

Question.5. What does protoplasm refer to?
Ans: Protoplasm refer to cytoplasm and nucleus.

Ques 6: Name two cells which keep changing their shape.
Answer: Amoeba and white blood cells.

Ques 7: Name the smallest cell and the longest cell in human body.
Ans: The smallest cell is the red blood cell or sperm cell in male. Longest cell is the nerve cell.

Ques 8: Name 3 features seen/present in almost every cell.
Ans: Plasma membrane, nucleus and cytoplasm.

Ques 9: What is diffusion?
Ans: When gases like C0₂, 0₂, move across the cell membrane, this process is called diffusion.

Ques 10: What is osmosis? This takes place from high water concentration to low water concentration.
Ans: The movement of water molecules through a selectively permeable membrane is called osmosis. This takes place from high water concentration to low water concentration.

Ques 11: What is the full form of DNA?
Ans: DNA —> Deoxyribo Nucleic Acid.

Ques 12: What is the function of chromosome?
Answer: Chromosomes contain information for the inheritance of features from parents to next generation in the form of DNA molecules.

Ques 13: Name the organelles present in liver of animals for detoxifying many poisons and drugs.
Ans: In the liver of animal cells smooth endoplasmic reticulum helps in detoxifying many poisons and drugs.

Ques 14: What is the energy currency of the cell?
Ans: ATP—Adenosine Triphosphate.

Ques 15: What is the function of ribosome?
Ans: Ribosomes help in protein synthesis.

Ques 16. Where are genes located in the cell?
Ans: Genes are located in the chromosomes in the nucleus of the cell.

Ques 17: Name the cell organelles that helps in packaging?
Ans: Golgi apparatus.

Ques 18: Name the cell organelle which helps in the transportation of material.
Ans: Endoplasmic reticulum.

Ques 19: Name the cell organelle due to which leaves, flowers and fruits get their colour.
Ans: Chromoplast.

Ques 20: Name the cell organelle which helps in the formation of lysosome.
Ans: Golgi apparatus.

Ques 21: Name the cleansing organelle in the cell.
Ans: Lysosomes.

Ques 22: Name two cells with cell wall.
Ans: Onion cell (plant cell) and fungi.

Ques 23: Why does mitochondria have largely folded inner membrane?
Ans: Mitochondria is the site for cellular respiration and provides energy to the cell. The largely folded inner membrane provides the increased surface area for ATP-generating chemical reactions.

Ques 24: Which organelle makes the digestive enzyme of lysosome?
Ans: Rough endoplasmic reticulum makes the digestive enzyme of lysosomes.

Ques 25: What are cisterns?
Ans: The golgi bodies consist Of a system of membrane-bound vesicles arranged in stacks called cisterns.

Short Answer Type Questions

Ques 1: State two conditions required for osmosis.
Ans: (i) The difference in the concentration of water, one should have higher concentration than the other.
(ii) Semi-permeable membrane is also required through which water will flow.

Ques 2: What is plasmolysis?
Ans: When a living plant cell loses water through osmosis there is shrinkage or contraction of the contents of the cell away from the cell wall. This phenomenon is known as plasmolysis.

Ques 3: How does fungi and bacteria can withstand much greater changes in the surrounding medium than animal cells?
Ans: The cell wall present in fungi and bacteria permits these cells to withstand very dilute external medium without bursting.
The cells take up water by osmosis, swells, and builds the pressure against the cell wall. The wall exerts an equal pressure against the swollen cell. It is because of the cell wall, such cells can withstand much greater changes in the surrounding medium than animal cells.

Ques 4: Give the function of nuclear membrane.
Ans: The nuclear membrane present as outer covering in the nucleus allows the transfer of material inside and out of the nucleus to cytoplasm.

Ques 5: Name the cell-organelles that have their own DNA and ribosomes.
Ans: The cell organelles with their own DNA and ribosomes are mitochondria and plastids.

Ques 6: State the difference between smooth endoplasmic reticulum and rough endoplasmic reticulum.
Ans:

Ques 7: What is endocytosis?
Ans: The cell membranes flexibility allows the cell engulf in food and other material from its external environment. This process is known as endocytosis. E.g., Amoeba acquires its food through such processes.

Ques 8: What is the function of vacuoles?
Ans: Vacuoles are storage sacs for solid or liquid content. In plant cells it provides turgidity and rigidity to the cell. In single-celled organisms vacuoles store food, e.g., Amoeba.

Ques 9: When we put raisins in water, why do they swell?
Ans: Raisins are dry with less water inside, when they are kept in water, osmosis takes place, water flows through the cell wall, cell membrane of the raisins and therefore it swells.

Ques 10: Why are lysosomes called suicidal bags?
Ans: Lysosomes contain digestive enzymes in it and helps in the cleaning of cell by digesting any foreign materials entering the cell, such as bacteria, food and old cell organelles.
When the lysosomes burst, the digestive enzyme digest its own cell. Hence it is called as suicidal bag.

Ques 11: What is nucleoid?
Ans: The nuclear region in some cells are poorly defined due to the absence of a nuclear membrane, it contains only nucleic acid. This undefined nuclear region with nucleic acid in it is called nucleoid.

Ques 12: What is the role, of cell organelles in the cell?
Ans: Each kind of cell organelles performs a specific function such as making new material, clearing of the waste, transporting material, etc.

Ques 13: Label the figure and answer the questions:
(i) A – It is the packaging organelle
(ii) B – Provides energy
(iii) C – helps in the transport of material
(iv) D – Carries the information.

Ans: (i) A – Golgi body
(ii) B – Mitochondria
(iii) C – Endoplasmic reticulum
(iv) D – Nucleus

Ques 14: What is the function of nucleus in a cell?
Ans: The nucleus plays a very important role in the reproduction of cells. It also helps the single cell to divide and form two new daughter cells.
It plays an important role in determining how the cell will develop and what form it will exhibit at maturity, by directing the chemical activities of the cell.

Ques 15: What is the Junction of plastids?
Ans: Plastids are present only in plant cells. There are two types of plastids chromoplasts (coloured plastids) and leucoplasts (white or colourless)
Chromoplast—Consists of coloured pigments and gives different colours to flowers, fruits and leaves. The green colour pigment present in leaf is called chlorophyll which helps in the photosynthesis and a plastid with chlorophyll is called chloroplast.
Leucoplast—It stores starch, oil and protein granules in it.

Ques 16: Do vacuoles store some material? If yes, name them.
Ans: Yes, vacuoles also store some important substances required in life of the plant cell. These are amino acids, sugars, various organic acids and some proteins. In some unicellular organisms, e.g. Amoeba, vacuoles also store food.

Ques 17: Explain the structure and function of Golgi bodies.
Ans: Structures: Golgi bodies consist of a system of membrane-bound vesicles arranged in stacks parallel to each other called cisterns. These membranes have connections with the membrane of endoplasmic reticulum (ER).
Functions:
(1) The material synthesised near the ER is packaged and dispatched to various target inside and outside the cell through Golgi apparatus.
(2) It also stores, modifies and helps in the packaging of products in vesicles.
(3) In some cases, complex sugars may be made from simple sugars in it.
(4) It also helps in the formation of lysosomes.

Ques 18: What are ribosomes? Where are they located in the cell? What is their function?
Ans: Ribosomes are spherical organelles present in the cell which are either freely distributed in the cytoplasm or may be attached to the endoplasmic reticulum.
It consists of ribosomal RNA (Ribonucleic acid) and proteins.
Functions of Ribosomes: It helps in the synthesis of proteins.

Ques 19: What is the difference in chromatin, chromosomes and gene?
Ans: (1) Chromatin: It is a fine network of thread-like structure made up of DNA or RNA. It gets condense to form chromosomes.
(2) Chromosome: The chromosomes are made from chromatin material and are located iri the cell.
(3) Genes are found in chromosomes.

Ques 20: Why do plant cells have more in number and big-sized vacuoles as compared to the animal cells?
Ans: Plant cells attain turgidity and rigidity due to the more number of vacuoles as well as large-sized vacuoles help the plant cells to withstand the wear and tear, external environmental conditions.
They also help in the storage of essential material required by plants for their growth like amino acids, sugar and various organic substances.

Ques 21: Explain the following terms:
(a) Plasma membrane
(b) Cytoplasm
(c) Nucleus.
Ans: (a) Plasma membrane: It is a thin membrane which controls the passage of materials in and out of the cell. It is also called as selectively permeable membrane. It makes the outer boundary of the cell and is made up of lipo-protein,
(b) Cytoplasm: It is transparent jelly-like thick substance present in the cell. It makes the ground of the cell in which all the cell organelles are suspended.
(c) Nucleus: It is a double-layered membrane structure which contains chromosomes required for the inheritance of characteristics from one generation to the other.

Ques 22: What is membrane biogenesis?
Ans: The endoplasmic reticulum helps in the manufacture of proteins and fat molecules or lipids which are important for the cell function. These proteins and lipids help in the building of the cell membrane. This process is known as membrane biogenesis.

Ques 23: Which organelle is known as powerhouse of the cell?
Ans: Mitochondria is known as powerhouse of the cell because they store energy in the form of ATP. [Adenosine Triphosphate]

Ques 24: What are genes?
Ans: Gene is a segment of DNA. They are located on chromosomes in linear fashions. One gene may perform one or more function. Genes are carrier of genetic codes.

Question 25. Draw various cells of human body.
Answer:

Long Answer Type Questions

Ques 1: Give five points of differences between plant cell and animal cell.
Ans:

Ques 2: Give five points of differences between prokaryotic cell and eukaryotic cell.
Ans:

Ques 3: Draw a neat labelled diagram of plant cell and label its parts.
Ans:

Ques 4: Draw a neat labelled diagram of animal cell.
Ans:

Ques 5: Name the cell organelle for the following:
(a) Present only in plant cell, provides strength and rigidity to the cell.
(b) It is the site for lipids synthesis and helps in detoxification of drugs.
(c) The inner membrane is folded to form cristae, it has its own DNA and proteins.
(d) It helps in the formation of lysosomes.
(e) It imparts colour to the fruit and flowers.
Ans: (a) Cell wall
(b) Smooth endoplasmic reticulum
(c) Mitochondria
(d) Golgi apparatus
(e) Chromoplast

Value-Based Questions

Ques 1: Vasu was helping his mother in laying the table when they had some guest for dinner. Vasu was about to sprinkle salt on salad for dressing. His mother stopped him from doing so and told him that it is too early to sprinkle salt on the salad, he should do so only when they are seated for having the dinner.
(a) What would happen if salt is sprinkled on the salad?
(b) Which property of cells is seen in adding salt to it?
(c) What value of Vasu is seen?
Ans: (a) On sprinkling of some salt on the salad, the salad will release water.
(b) The salt outside the salad acts as hypertonic solution as it has less water concentration and therefore the cell looses water by osmosis.
(c) Vasu showed the value of being very helpful, caring and responsible.

Ques 2: Anu is a five year old girl who joined the swimming classes. After the first class she was worried when she saw her wrinkled fingers. She asked her elder sister about the wrinkling and shrinking of her fingers. Her sister explained Anu why it was so.
(a) Why did the fingers wrinkle after swimming?
(b) What caused the shrinking/wrinkling of fingers?
(c) What value of Anu is seen in the above cast?
Ans: (a) Fingers wrinkled because the cells of the skin lost some water.
(b) This happened because of the difference in the concentration of water in the skin cells and swimming pool’s water.
(c) Anu showed the value of aware citizen and a good learner who clarifies the doubts.

Ques 3: Two sailors got marooned on the island, both of them were very thirsty and one of the sailors tried to drink sea water. The other sailor immediately stopped him from drinking the salty water of sea and suggested to wait for some help, stay calm and patient.
(a) What would happen if the sailor drinks salty water?
(b) What is osmosis?
(c) What value of sailors is reflected in the above act?
Ans: (a) On drinking sally water, exosmosis in the intestine will cause dehydration and vomiting.
(b) The movement of water molecules through a permeable membrane is called osmosis.
(c) Sailors showed the value of being patient, composed, empathy and determination.

Ques 4: Sachin’s mother wanted to use some eggs for incubation. Sachin helped his mother in separating rotten and spoilt eggs from the good ones. He took a bucket of water to separate them.
(a) How can one separate the rotten eggs from the good ones using water?
(b) What is the shell of egg made up of?
(c) What value of Sachin is seen in this act?
Ans: (a) We can separate the rotten eggs by dipping them in water. The eggs that will float in water are rotten eggs and the one that sinks are good one.
(b) Egg shell is made up of calcium carbonate.
(c) Sachin showed the value of being helpful, responsible behaviour.