ICSE Class 10

General instructions: Answer all questions. Marks are shown in brackets [ ].

Objective

1. 1.
   Which of the following values correctly represents 1 kWh in joules?

   1. A. 3.6 × 10³ J
   2. B. 3.6 × 10⁶ J
   3. C. 3.6 × 10⁵ J
   4. D. 3.6 × 10⁴ J
   [1]
2. 2.
   What is meant by the kinetic energy of a body?

   1. A. The energy possessed by a body due to its motion.
   2. B. The energy stored in a body due to its position or shape.
   3. C. The force required to bring a moving body to rest.
   4. D. The work done by a body when it comes to rest.
   [1]
3. 3.
   A ball of mass 200 g falls from a height of 5 m. What is its kinetic energy when it just reaches the ground? (Take g = 9.8 ms⁻²)

   1. A. 4.9 J
   2. B. 9.8 J
   3. C. 19.6 J
   4. D. 2.45 J
   [1]
4. 4.
   Which of the following correctly defines the term energy and states its S.I. unit?

   1. A. Energy is the capacity to do work. Its S.I. unit is the joule (J).
   2. B. Energy is the force applied to an object. Its S.I. unit is the newton (N).
   3. C. Energy is the rate of doing work. Its S.I. unit is the watt (W).
   4. D. Energy is the distance moved per unit time. Its S.I. unit is the meter per second (m/s).
   [1]
5. 5.
   SI unit of power is

   1. A. joule. hour.
   2. B. watt
   3. C. watt hour
   4. D. kilowatt
   [1]
6. 6.
   Which of the following correctly expresses the relationship between 1 kWh and 1 J?

   1. A. 1 kWh = 1000 J
   2. B. 1 kWh = 3.6 × 10³ J
   3. C. 1 kWh = 3.6 × 10⁶ J
   4. D. 1 kWh = 36 × 10⁵ J
   [1]
7. 7.
   A body of mass 5 kg is thrown vertically upwards with an initial velocity of 10 m/s. Calculate the work done by gravity when the body reaches its maximum height. (Take g = 9.8 m/s²).

   1. A. -250 J
   2. B. 250 J
   3. C. -490 J
   4. D. 50 J
   [1]
8. 8.
   A truck weighing $5 \times 10^{3}\,\mathrm{kgf}$ and a cart weighing $500\,\mathrm{kgf}$ are moving with the same speed. How do their kinetic energies compare?

   1. A. The kinetic energy of the truck is 10 times that of the cart.
   2. B. The kinetic energy of the cart is 10 times that of the truck.
   3. C. The kinetic energy of the truck is 5 times that of the cart.
   4. D. Both have the same kinetic energy since their speeds are equal.
   [1]
9. 9.
   A ball of mass 0.20 kg is thrown vertically upwards with an initial velocity of 20 ms⁻¹. What is the maximum potential energy it gains as it goes up?

   1. A. 20 J
   2. B. 40 J
   3. C. 60 J
   4. D. 80 J
   [1]
10. 10.
    Which graph correctly represents the potential energy vs height for a body thrown vertically upwards, assuming no friction is present?

    1. A. A straight line with positive slope starting from zero at ground level.
    2. B. A straight line with negative slope starting from zero at ground level.
    3. C. A parabolic curve opening upwards.
    4. D. A horizontal line at a constant potential energy.
    [1]
11. 11.
    A coolie X carrying a load on his head climbs up a slope and another coolie Y carrying the identical load on his head moves the same distance on a frictionless horizontal platform. Who does more work?

    1. A. Coolie X does more work because he works against gravity.
    2. B. Coolie Y does more work because the platform is frictionless.
    3. C. Both coolies do the same work since the load and distance are identical.
    4. D. Neither coolie does any work because the load is carried on the head.
    [1]
12. 12.
    If the speed of a car is halved, how does its kinetic energy change?

    1. A. It becomes one-fourth of its original value.
    2. B. It becomes half of its original value.
    3. C. It becomes one-eighth of its original value.
    4. D. It doubles its original value.
    [1]
13. 13.
    An ox can apply a maximum force of 1000 N. It is taking part in a cart race and is able to pull the cart at a constant speed of 30 m s⁻¹ while making its best effort. What is the power developed by the ox?

    1. A. 30 W
    2. B. 3 kW
    3. C. 30 kW
    4. D. 300 kW
    [1]
14. 14.
    A body is thrown vertically upwards. Its velocity keeps on decreasing. What happens to its kinetic energy as its velocity becomes zero?

    1. A. Kinetic energy remains constant.
    2. B. Kinetic energy reduces to zero.
    3. C. Kinetic energy increases.
    4. D. Kinetic energy converts into heat.
    [1]
15. 15.
    What is meant by degradation of energy, illustrated with an example from daily life?

    1. A. The complete loss of energy from a system, such as a car engine stopping when fuel runs out.
    2. B. The conversion of energy into an undesirable or non-useful form, like an incandescent bulb producing more heat than light.
    3. C. The transfer of energy from one object to another without any loss, such as a ball bouncing perfectly.
    4. D. The increase in energy efficiency over time, like modern LED bulbs using less power than older bulbs.
    [1]
16. 16.
    Calculate the kinetic energy of a body of mass 5 kg momentum 50 kg ms⁻¹.

    1. A. 250 J
    2. B. 158 J
    3. C. 375 J
    4. D. 279 J
    [1]
17. 17.
    The bob of a simple pendulum is imparted a velocity of 5 m s⁻¹ when it is at its mean position. To what maximum vertical height will it rise on reaching its extreme position if 60% of its energy is lost in overcoming the friction of air? (Take g = 10 m s⁻²).

    1. A. 0.5 m
    2. B. 0.75 m
    3. C. 1.25 m
    4. D. 2.0 m
    [1]
18. 18.
    An electric pump is 60% efficient and is rated 2 HP. Calculate the maximum amount of water it can lift through a height of 5 m in 40 s. [Take g = 10 ms⁻² and 1 HP = 750 W]

    1. A. 25 kg
    2. B. 38 kg
    3. C. 720 kg
    4. D. 280 kg
    [1]
19. 19.
    A boy pulls a toy car with a force of 50 N through a string making a 30° angle with the horizontal, moving it 1 m horizontally. If the string were inclined at 45°, what force would he need to apply along the string to move it the same 1 m distance? (Given cos 30° = 0.8667, cos 45° = 0.7071)

    1. A. 61.27 N
    2. B. 50.00 N
    3. C. 70.71 N
    4. D. 86.60 N
    [1]
20. 20.
    Two bodies of masses m₁ and m₂ have the same linear momenta. The ratio of their kinetic energies is:

    1. A. m₁ : m₂
    2. B. m₂ : m₁
    3. C. m₁² : m₂²
    4. D. √m₁ : √m₂
    [1]