Class 7 Science: Sample Paper Solutions - 4 | Sample Papers For Class 7 PDF Download

Time: 3 Hours  
Total Marks: 80

General Instructions

This question paper consists of 34 questions in total and all questions are compulsory.

• Questions 1-7 are multiple-choice questions and carry 1 mark each. Write the correct answer in your answer sheet.
• Questions 8-17 are very short answer questions and carry 2 marks each.
• Questions 18-28 are short answer questions and carry 3 marks each.
• Questions 29-34 are long answer questions and carry 5 marks each.

Section - A

Q1. Which substance is used to neutralise bee sting pain? (1 Mark)
(a) Vinegar 
(b) Baking soda 
(c) Lemon juice 
(d) Sugar solution

Ans: (b) Baking soda
Baking soda neutralises formic acid in bee stings.

Q2. What is the function of a switch in a circuit? (1 Mark)
(a) Conducts current 
(b) Breaks circuit 
(c) Generates electricity 
(d) Measures voltage

Ans: (b) Breaks circuit
A switch controls current flow by opening or closing the circuit.

Q3. Which non-metal is essential for breathing? (1 Mark)
(a) Carbon 
(b) Sulphur 
(c) Oxygen 
(d) Nitrogen

Ans: (c) Oxygen
Oxygen is used by animals for respiration.

Q4. What type of change is rusting of iron? (1 Mark)
(a) Physical 
(b) Chemical 
(c) Reversible 
(d) Temporary

Ans: (b) Chemical
Rusting forms iron oxide, a new substance.

Q5. What causes increased sweating in adolescence? (1 Mark)
(a) Muscle growth 
(b) Active sweat glands 
(c) Bone growth 
(d) Hair growth

Ans: (b) Active sweat glands
Sweat glands become active during puberty.

Q6. Which surface reflects light regularly? (1 Mark)
(a) Rough 
(b) Smooth 
(c) Uneven 
(d) Dull

Ans: (b) Smooth
Smooth surfaces like mirrors reflect light regularly.

Q7. What is the time period of Earth’s rotation? (1 Mark)
(a) 365 days 
(b) 24 hours 
(c) 12 hours 
(d) 1 month

Ans: (b) 24 hours
Earth’s rotation takes 24 hours, causing day and night.

Section - B

Q8. What is a base? (2 marks)

Ans: A base is a substance that neutralises acids.
For example, sodium hydroxide turns red litmus blue.

Q9. What is a conductor in electricity? (2 marks)

Ans: A conductor allows electric current to pass through.
For example, copper wires conduct electricity.

Q10. Name two physical properties of metals. (2 marks)

Ans: Metals are lustrous and can be shaped.
For example, gold shines and is malleable.

Q11. What is a chemical change? (2 marks)

Ans: A chemical change forms new substances.
For example, burning wood produces ash (NCERT Chapter 6).

Q12. What is the role of exercise in adolescence? (2 marks)

Ans: Exercise strengthens muscles and bones during adolescence.
For example, running improves stamina.

Q13. What is convection in liquids? (2 marks)

Ans: Convection transfers heat by liquid movement.
For example, boiling water circulates heat.

Q14. What is a speedometer? (2 marks)

Ans: A speedometer measures a vehicle’s speed.
For example, it shows car speed in km/h.

Q15. What is the function of arteries? (2 marks)

Ans: Arteries carry oxygenated blood from the heart.
For example, the aorta supplies blood to the body.

Q16. What is heterotrophic nutrition? (2 marks)

Ans: Heterotrophic nutrition involves consuming other organisms.
For example, animals eat plants or meat.

Q17. What is a virtual image? (2 marks)

Ans: A virtual image cannot be projected on a screen.
For example, plane mirrors form virtual images.

Section - C

Q18. How is litmus used to test acids? (3 marks)

Ans:

• Litmus is an indicator that changes colour in acids.
• Blue litmus turns red in acidic solutions.
  For example, hydrochloric acid turns blue litmus red.

Q19. What is the role of insulators in circuits? (3 marks)

Ans:

• Insulators prevent unwanted flow of electric current.
• They protect users from electric shocks.
• For example, rubber coating on wires.

Q20. How do metals react with acids? (3 marks)

Ans:

• Metals react with acids to produce hydrogen gas.
• A salt is formed during the reaction.
• For example, zinc and hydrochloric acid form zinc chloride.

Q21. What is a neutralisation reaction? (3 marks)

Ans:

• Neutralisation combines acid and base to form salt and water.
• It cancels their acidic and basic properties.
  For example, sodium hydroxide neutralises hydrochloric acid.

Q22. What is the importance of sleep in adolescence? (3 marks)

Ans:

• Sleep supports physical and mental growth in adolescence.
• It helps in memory and emotional regulation.
  For example, 8–10 hours of sleep is needed.

Q23. How does a clinical thermometer work? (3 marks)

Ans:

• A clinical thermometer measures body temperature accurately.
• Mercury or alcohol expands with heat to show temperature.
  For example, used to check fever.

Q24. How is time measured using a pendulum? (3 marks)

Ans:

• A pendulum’s swing completes a fixed time period.
• Time is measured by counting swings.
  For example, a stopwatch tracks pendulum swings.

Q25. What is the role of veins in circulation? (3 marks)

Ans:

• Veins carry deoxygenated blood to the heart.
• They have valves to prevent backflow.
  For example, pulmonary veins carry oxygenated blood.

Q26. How do leaves help in transpiration? (3 marks)

Ans:

• Leaves lose water vapour through stomata in transpiration.
• This process pulls water from roots.
  For example, trees release water in hot weather.

Q27. What is the difference between convex and concave lenses? (3 marks)

Ans:

• Convex lenses converge light rays; concave lenses diverge them.
• Convex lenses form real or virtual images; concave form virtual 
  For example, convex in magnifying glasses.

Q28. What is the shape of the Moon’s orbit around Earth? (3 marks)

Ans:

• The Moon’s orbit around Earth is elliptical.
• It takes about 27.3 days to complete one orbit.
  For example, it causes phases of the Moon.

Section - D

Q29. (a) What is the role of stomata in plants? 
(b) Explain their function in gas exchange. 
(c) Draw a labelled diagram of stomata. (5 marks)

Ans:

• Stomata are tiny pores on plant leaves for gas exchange.
• They allow carbon dioxide in for photosynthesis and oxygen out.
• Guard cells control opening and closing of stomata.
  For example, stomata regulate water loss in leaves.

Q30. (a) What are mineral acids? 
(b) Explain their properties. 
(c) Why are they used industrially? (5 marks)

Ans:

• Mineral acids are strong acids derived from minerals.
• They ionise completely in water and are corrosive.
• They react with metals to produce hydrogen gas.
  For example, sulphuric acid is used in batteries.
• They are vital in industries for cleaning and manufacturing.

Q31. (a) What is an electric circuit? 
(b) Explain its components. 
(c) Draw a labelled diagram of a simple circuit. (5 marks)

Ans:

• An electric circuit is a path for current flow.
• It includes a cell, wires, switch, and load.
• The switch controls the circuit; wires conduct current.
  For example, a torch circuit lights a bulb.

Q32. (a) What is corrosion? 
(b) Explain methods to prevent it. 
(c) Why is it harmful? (5 marks)

Ans:

• Corrosion is the chemical damage of metals by air or water.
• Prevention includes painting, galvanizing, or oiling metals.
• Galvanizing coats iron with zinc to block moisture.
  For example, iron rusts in moist air.
• It weakens structures and tools.

Q33. (a) What is the role of hormones in adolescence? 
(b) Explain two hormones and their effects. 
(c) Why are they important? (5 marks)

Ans:

• Hormones regulate physical and emotional changes in adolescence.
• Testosterone causes voice deepening; oestrogen triggers menstruation.
• Hormones are secreted by glands like the pituitary.
  For example, growth hormone increases height.
• They prepare the body for reproductive maturity.

Q34. (a) What is the role of the Sun in the water cycle? 
(b) Explain its effect on evaporation. 
(c) Why is it important? (5 marks)

Ans:

• The Sun provides energy for the water cycle.
• It heats water bodies, causing evaporation into vapour.
• Evaporation leads to cloud formation and precipitation.
  For example, Sun evaporates water from rivers.
• It sustains water availability for life.