Text Book Solutions All Class

Q1: What is the main reason for the development of pimples during adolescence?

a) ​Lack of sleep

b) Increase in oily secretions from the skin

c) Excessive washing of the face

d) Change in diet

Q2: What is the term used to describe the natural signs that the body is preparing for adulthood?

a) Puberty

b) Maturity

c) Secondary sexual characteristics

d) Adolescence

Q3: At what age does adolescence typically begin?

a) 5–6 years

b) 10–12 years

c) 13–14 years

d) 19–20 years

Q4: What does the onset of the menstrual cycle in girls indicate?

a) Beginning of adolescence

b) The start of puberty

c) Both a and b

d) End of childhood

Q5: Which of the following is a secondary sexual characteristic in boys?

a) Development of breasts

b) Voice deepening

c) Menstruation

d) None of the above2. Fill in the Blanks:

Q1: The stage of life when the body undergoes changes to prepare for adulthood is called __________.

Q2: The growth of facial hair in boys is one of the __________ sexual characteristics that occur during adolescence.

Q3: The natural process in adolescent girls that involves the release of blood is called __________.

Q4: During adolescence, boys and girls experience growth in __________ in the pubic region and underarms.

Q5: __________ refers to the time period when the body undergoes internal and external changes to reach reproductive capability.3. True/False Questions:

Q1: Adolescence is marked only by physical changes in the body.

Q2: The onset of menstruation is an important internal change in adolescent girls.

Q3: Acne is a common skin condition that may develop due to increased oily secretions during adolescence.

Q4: Boys and girls develop the same type of secondary sexual characteristics during adolescence.

Q5: The menstrual cycle is an indicator of a girl’s reproductive health.Very Short Answer Questions:

Q1: What are secondary sexual characteristics?

Q2: What is menstruation?

Q3: Why do boys experience voice changes during adolescence?

Q4: How does physical activity help adolescents?

Q5: What is the role of hormones during adolescence?Long Answer Questions:

Q1: Explain the physical and emotional changes that occur during adolescence.

Q2: How can adolescents manage emotional changes effectively?

Q3: What are the key nutritional needs of adolescents, and why are they important?

Q4: What is the significance of the menstrual cycle in adolescent girls?

Q5: Discuss the impact of substance abuse during adolescence and the importance of saying ‘NO’ to harmful substances.

You can find Worksheets Solutions here: Worksheet Solutions: Adolescence: A Stage of Growth and Change

Q.1. True/False

(i) Rusting of iron is a physical change.

(ii) Evaporation of water is a reversible change.

(iii) All physical changes are reversible.

(iv) Burning of magnesium ribbon produces a white powder.

(v) Bioluminescence produces light without heat.

Q.2. Fill in the blanks.

(i) Cutting a log of wood into pieces is a ____ change.

(ii) Condensation is a ____ change.

(iii) When carbon dioxide is passed through lime water, it turns milky due to the formation of ____.

(iv) Two methods by which rusting of iron can be prevented are ____ and ____.

(v)  Changes in which only ____ properties of a substance change are called physical changes.

(vi)  A medicine is the end product of a chain of ____.

​Answer the following Questions

Q3. What is the white substance formed when lime water reacts with carbon dioxide?

Q4. What kind of change is chopping vegetables?

Q5. Name the three requirements of the fire triangle.

Q6. Which process breaks down rocks into soil over time?

Q7. What kind of change is melting wax?

Q8. What happens when magnesium ribbon is burnt in air?
Q.9. What do you understand by chemical change?
Q.10. Why formation of manure from leaves is a chemical change?

Q.11. Why tearing of paper into pieces is a physical change?

Q.12. What is rusting?

Q.13. Explain why burning of wood and cutting it into small pieces are considered as two different types of changes.

Q.14. What is a physical change?

Q.15. Explain the changes that occur when a candle burns.

​You can find Worksheets Solutions here: Worksheet Solutions: Physical and Chemical Changes 

Q1: Which metal is commonly used to make food packaging materials as it is cheaper, and its thin sheets can be folded easily into any shape?

a) Aluminium

b) Copper

c) Iron

d) Gold

Q2: Which of the following metals catches fire when it comes in contact with water?

a) Copper

b) Aluminium

c) Zinc

d) Sodium

Q3: Which of the following properties do most metals possess?

a) Malleability

b) Dullness

c) Non-conductivity

d) Brittle

Q4: Which of these metals is known for being the most malleable and ductile?

a) Gold

b) Copper

c) Iron

d) Aluminium

Q5: What is the property that enables metals to produce a ringing sound when struck?

a) Malleability

b) Sonority

c) Ductility

d) LustreFill in the Blanks:

Q1: Materials that allow electricity to flow through them easily are called __________.

Q2: The property of metals by which they can be beaten into thin sheets is called __________.

Q3: Metals react with oxygen to produce __________ which are basic in nature.

Q4: The process of formation of rust on objects made of iron is called __________.

Q5: The property by which materials can be drawn into wires is called __________.True/False Questions:

Q1: All metals are hard and lustrous.

Q2: Non-metals are generally poor conductors of heat and electricity.

Q3: Metals do not react with oxygen.

Q4: The rusting of iron can be prevented by applying a protective layer of zinc.

Q5: Magnesium burns with a dazzling white flame and forms a white powder when exposed to oxygen.Very Short Answer Questions:

Q1: What is the process by which metals like iron develop brown deposits?

Q2: What is the property of metals that allows them to be beaten into thin sheets?

Q3: Why are materials like copper and aluminium used in electrical wiring?

Q4: What happens when magnesium reacts with oxygen?

Q5: What is the nature of magnesium oxide when dissolved in water?Long Answer Questions:

Q1: Explain the properties of metals and non-metals and how they differ.

Q2: Why are gold and silver used in jewellery, and why are only a few metals suitable for this purpose?

Q3: Describe the process of rusting and the methods used to prevent it.

Q4: How do the properties of metals and non-metals influence their uses in everyday life?

Q5: What is the significance of the Iron Pillar of Delhi, and what does it tell us about ancient Indian metallurgy?

You can find Worksheets Solutions here: Worksheet Solutions: The World of Metals and Non-metals​

Q.1. True/False

(i) The human body is a good conductor of electricity.

(ii) An incandescent lamp will not glow if connected with the wrong terminals.

(iii) Circuit diagrams use symbols to show real components in a circuit.

(iv) A battery produces alternating current (AC).

(v) LEDs can work even if the positive and negative terminals are reversed.

Q.2. Fill in the blanks.

(i) Longer line in the symbol for a cell represents its ____ terminal.

(ii) The combination of two or more cells is called a ____.

(iii) When current is switched ‘on’ in a room heater, it ____.

(iv) The safety device based on the heating effect of electric current is called a ____.

Answer the following Questions 

Q.3. What is electric current?

Q.4. Write some uses of battery.

Q.5. What is filament?

Q.6. What are the uses of heating effect of electric current?

Q.7. Name any two effects of electric current.

Q.8. What is an electric circuit?

Q.9. Explain the symbol of electric cell.

Q.10. Why a fused bulb does not glow?

Q.11. Sometimes the cells are placed side by side. Then how are the terminals of the cells connected?

Q.12. What is a switch, and how does it control an electric circuit?

Q.13. Explain the importance of circuit diagrams and list three symbols used.

Q.14. Describe the difference between an incandescent lamp and an LED.

Q.15. What are conductors and insulators? Give examples and their uses.

You can find Worksheets Solutions here: Worksheet Solutions: Electric Current and Its effects 

Q.1. True/False

(i) Nitric acid turns red litmus blue.

(ii) Sodium hydroxide turns blue litmus red.

(iii) Sodium hydroxide and hydrochloric acid neutralize each other and form salt and water.

(iv) An indicator is a substance that shows different colors in acidic and basic solutions.

(v) Tooth decay is caused by the presence of a base.

(vi) If an indicator changes color with a base, it does not change color with an acid.

Q.2. Fill in the blanks.

(i) Change of color in an acid and a base depends on the type of the ____.

(ii) Acid turns ____ litmus red.

(iii) Bases turn ___ litmus blue.

(iv) Litmus has a ____ color in distilled water.

(v) In the neutralization reaction a new substance is formed. This is called ____.

(vi)  Lemon juice is ____ in nature.

Answer the following Questions 

Q.3. Why do curd, lemon juice, orange juice, and vinegar taste sour?

Q.4. Tom rubs a solution between his fingers and feels soapy, what is the nature of that solution?

Q.5. What do you mean by neutral solution? Give examples.

Q.6. State a few properties of acids.

Q.7. Which acid is present in an ant sting?

Q.8. What is the nature of distilled water?

Q.9. Which is the most commonly used natural indicator?

Q.10. Blue litmus paper is dipped in a solution. It remains blue. What is the nature of the solution? Explain.

Q.11. Why factory waste is neutralised before disposing it of in the water bodies?

Q.12. Give some examples of acids and bases that we encounter in day-to-day life.

Q.13. What is the effect of the China rose indicator on acidic and basic solutions?

Q.14. Why a turmeric stain on my white shirt is turned to red when it is washed with soap.

Q.15. Is the distilled water acidic/basic/neutral? How would you verify it?

Multiple Choice Questions

Q1: What is the primary goal of science as mentioned in the chapter?

a) To memorize facts

b) To explore the world through curiosity and experiments

c) To study historical events

d) To prove theories

ExperimentingQ2: Which of the following is an example of a reversible change?

a) Burning of paper

b) Breaking of a rock

c) Melting of ice

d) Rusting of iron

Q3: What inspired the early scientific exploration of flight?

a) Observing the movement of the sun

b) Experimenting with electricity

c) Watching planes fly

d)  Studying the wings of birds

Exploration of FlightQ4: What does science help us do according to the chapter?

a) Answer only factual questions

b) Develop new technologies

c) Understand and explore the environment

d) Memorize important dates

Q5: What does the chapter suggest about human activities and nature?

a) They are not connected

b) They are linked and affect the environment

c) Human activities have no impact on nature

d) Human activities only affect animalsFill in the Blanks

Q1. Science is not just about discovering facts but also about _______ curiosity and asking questions.

Q2. The process of light and shadows helped early humans to measure _______.

Measuring TimeQ3. Materials are classified based on their _______ such as conductivity or malleability.

Q4. Animals breathe and circulate _______ to all parts of their body for survival.

Q5. The phenomenon of eclipses is caused by the _______ cast by Earth or Moon.True/False Questions

Q1: Science is about memorizing facts and repeating them.

Q2: Human activities are connected to the natural world and impact the environment.

Q3: The chapter encourages only studying the properties of materials and not asking any questions.

Science is about CuriosityQ4: The position of shadows in the Sun was used by early humans to measure time.

Q5: The study of light and shadows does not help in understanding the Earth’s movements.Short Answer Questions

Q1. Explain how science is a continuous process of discovery.

Q2. What is the difference between reversible and irreversible changes?

Q3. Why is it important to step outside the classroom to learn science?

Q4. How do human activities link to environmental challenges?

Our EnvironmentQ5. What role do light and shadows play in our daily life and in science?Long Answer Questions

Q1. Explain why science is considered both a process and a way of thinking.

Q2. Describe how different fields of science are interconnected and why this is important.

Q3. Why is hands-on learning through experiments and activities emphasized in science education?

Q4. Discuss the role of science in addressing environmental challenges and promoting sustainability.

Q5. How do light and shadows help us understand time and natural phenomena like eclipses?