Question 1

Q1. Which of the following changes is a chemical change?

Accepted Answer

Option C: Burning of magnesium ribbon. Burning magnesium forms magnesium oxide, a new substance with different properties. Hence, it is a chemical change.

Question 2

Q2. The ability of a lens to converge or diverge light rays depends on its:

Accepted Answer

Option B: Power. Power of a lens measures its ability to bend light rays and is expressed in dioptres.

Question 3

Q3. Which blood vessel carries oxygenated blood from lungs to heart?

Accepted Answer

Option D: Pulmonary vein. Pulmonary vein carries oxygen-rich blood from lungs to the left atrium of the heart.

Question 4

Q4. Which property makes graphite suitable for use in electrodes?

Accepted Answer

Option B: Good electrical conductivity. Graphite contains free electrons, making it a good conductor of electricity.

Question 5

Q5. Which of the following is an example of a biodegradable substance?

Accepted Answer

Option C: Vegetable peels. Biodegradable substances are decomposed naturally by microorganisms.

Question 6

Q6. A student places blue litmus paper in a colourless solution and it turns red. The solution is likely to have:

Accepted Answer

Option C: pH less than 7. Acids turn blue litmus red and have pH values less than 7.

Question 7

Q7. A boy standing in front of a plane mirror notices that when he moves 1 m toward the mirror, the distance between him and his image becomes:

Accepted Answer

Option B: 2 m. If the boy is 1 m from the mirror, image is also 1 m behind it. Total distance becomes 2 m. (Tricky mirror concept)

Question 8

Q8. During respiration, the breakdown of glucose releases energy stored in the form of:

Accepted Answer

Option A: ATP. ATP acts as the energy currency of cells and stores released energy.

Question 9

Q9. A student connects three resistors in parallel. The equivalent resistance will be:

Accepted Answer

Option C: Less than the smallest resistance. Parallel combination always decreases effective resistance below the smallest resistor.

Question 10

Q10. A white powder is used for whitewashing walls after mixing with water. The powder is:

Accepted Answer

Option B: Quicklime. Quicklime reacts with water to form slaked lime used in whitewashing.

Question 11

Q11. Solar cookers are generally painted black internally because black surfaces:

Accepted Answer

Option B: Absorb maximum heat. Black surfaces absorb more solar radiation, increasing heating efficiency.

Question 12

Q12. Assertion (A): Ionic compounds conduct electricity in molten state. Reason (R): Ions become free to move in molten state.

Accepted Answer

Option A: Both A and R are true and R is correct explanation of A. In molten state, ions are mobile and can carry electric current.

Question 13

Q13. Assertion (A): Plants use carbon dioxide during photosynthesis. Reason (R): Carbon dioxide is broken down to release oxygen.

Accepted Answer

Option C: A is true but R is false. Plants use carbon dioxide to prepare glucose. Oxygen released comes mainly from water molecules.

Question 14

Q14. Case Study: A student performed an experiment with iron nails placed in three test tubes: • Tube A: Nails in dry air • Tube B: Nails in boiled water covered with oil • Tube C: Nails in water and air Rusting was observed only in Tube C. This shows rusting requires:

Correct Answer: Option D (Both water and oxygen)

Concept Explanation: Rusting occurs only when both moisture and oxygen are present together.

Accepted Answer

Option D: Both water and oxygen. Rusting occurs only when both moisture and oxygen are present together.

Question 15

Q15. Case Study: A family replaces ordinary bulbs with LED bulbs. The electricity bill decreases because LEDs:

Accepted Answer

Option B: Convert more electrical energy into light. LEDs are energy-efficient and waste less energy as heat compared to ordinary bulbs.

Question 16

Q16. A student says that current is consumed in an electric circuit. Which statement is correct?

Accepted Answer

Option C: Current remains same in series circuit. Electric current is not consumed; charges continue flowing through the circuit. (Common misconception)

Question 17

Q17. Which of the following organisms can fix atmospheric nitrogen?

Accepted Answer

Option A: Rhizobium bacteria. Rhizobium lives in root nodules of leguminous plants and fixes atmospheric nitrogen.

Question 18

Q18. A convex lens forms a virtual image when the object is placed:

Accepted Answer

Option C: Between F and optical centre. When the object lies within focal length, the convex lens forms an erect virtual image. (High-frequency tricky concept)

Question 19

Q19. A hydrocarbon has molecular formula C ₂ H ₄ . It belongs to:

Accepted Answer

Option B: Alkene. Alkenes contain at least one double bond and follow the general formula C H ₂  .

Question 20

Q20. A student observes that an image formed by a concave mirror is erect and enlarged. The object is placed:

Accepted Answer

Option C: Between focus and pole. When an object is placed between focus and pole of a concave mirror, the image formed is virtual, erect, and magnified.

Mock Test 03 Performance Solutions

Detailed Question Analysis

Q1. Which of the following changes is a chemical change?

Q2. The ability of a lens to converge or diverge light rays depends on its:

Q3. Which blood vessel carries oxygenated blood from lungs to heart?

Q4. Which property makes graphite suitable for use in electrodes?

Q5. Which of the following is an example of a biodegradable substance?

Q6. A student places blue litmus paper in a colourless solution and it turns red. The solution is likely to have:

Q7. A boy standing in front of a plane mirror notices that when he moves 1 m toward the mirror, the distance between him and his image becomes:

Q8. During respiration, the breakdown of glucose releases energy stored in the form of:

Q9. A student connects three resistors in parallel. The equivalent resistance will be:

Q10. A white powder is used for whitewashing walls after mixing with water. The powder is:

Q11. Solar cookers are generally painted black internally because black surfaces:

Q12. Assertion (A): Ionic compounds conduct electricity in molten state. Reason (R): Ions become free to move in molten state.

Q13. Assertion (A): Plants use carbon dioxide during photosynthesis. Reason (R): Carbon dioxide is broken down to release oxygen.

Q14. Case Study: A student performed an experiment with iron nails placed in three test tubes: • Tube A: Nails in dry air • Tube B: Nails in boiled water covered with oil • Tube C: Nails in water and air Rusting was observed only in Tube C. This shows rusting requires:

Q15. Case Study: A family replaces ordinary bulbs with LED bulbs. The electricity bill decreases because LEDs:

Q16. A student says that current is consumed in an electric circuit. Which statement is correct?

Q17. Which of the following organisms can fix atmospheric nitrogen?

Q18. A convex lens forms a virtual image when the object is placed:

Q19. A hydrocarbon has molecular formula C 2 H 4 . It belongs to:

Q20. A student observes that an image formed by a concave mirror is erect and enlarged. The object is placed:

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Mock Test 03 Performance Solutions

Detailed Question Analysis

Q1. Which of the following changes is a chemical change?

Q2. The ability of a lens to converge or diverge light rays depends on its:

Q3. Which blood vessel carries oxygenated blood from lungs to heart?

Q4. Which property makes graphite suitable for use in electrodes?

Q5. Which of the following is an example of a biodegradable substance?

Q6. A student places blue litmus paper in a colourless solution and it turns red. The solution is likely to have:

Q7. A boy standing in front of a plane mirror notices that when he moves 1 m toward the mirror, the distance between him and his image becomes:

Q8. During respiration, the breakdown of glucose releases energy stored in the form of:

Q9. A student connects three resistors in parallel. The equivalent resistance will be:

Q10. A white powder is used for whitewashing walls after mixing with water. The powder is:

Q11. Solar cookers are generally painted black internally because black surfaces:

Q12. Assertion (A): Ionic compounds conduct electricity in molten state. Reason (R): Ions become free to move in molten state.

Q13. Assertion (A): Plants use carbon dioxide during photosynthesis. Reason (R): Carbon dioxide is broken down to release oxygen.

Q14. Case Study: A student performed an experiment with iron nails placed in three test tubes: • Tube A: Nails in dry air • Tube B: Nails in boiled water covered with oil • Tube C: Nails in water and air Rusting was observed only in Tube C. This shows rusting requires:

Q15. Case Study: A family replaces ordinary bulbs with LED bulbs. The electricity bill decreases because LEDs:

Q16. A student says that current is consumed in an electric circuit. Which statement is correct?

Q17. Which of the following organisms can fix atmospheric nitrogen?

Q18. A convex lens forms a virtual image when the object is placed:

Q19. A hydrocarbon has molecular formula C 2 H 4 . It belongs to:

Q20. A student observes that an image formed by a concave mirror is erect and enlarged. The object is placed:

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