ICSE Class 10

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

Objective

1. 1.
   Which of the following correctly defines the term heat?

   1. A. Heat is a form of energy that flows from a body at higher temperature to a body at lower temperature due to the temperature difference between them.
   2. B. Heat is the total kinetic energy possessed by the molecules of a body.
   3. C. Heat is the degree of hotness or coldness measured by a thermometer.
   4. D. Heat is a force that causes temperature to rise in a substance.
   [1]
2. 2.
   What is the term defined as 'the measurement of the quantity of heat'?

   1. A. Thermodynamics
   2. B. Calorimetry
   3. C. Heat capacity
   4. D. Specific heat
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3. 3.
   The S.I. unit of heat capacity is

   1. A. J kg⁻¹
   2. B. J K⁻¹
   3. C. J kg⁻¹ K⁻¹
   4. D. cal °C⁻¹
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4. 4.
   Define the term specific latent heat of fusion of ice and state its S.I. unit.

   1. A. The heat energy required to convert 1 kg of ice at 0°C to water at 0°C without temperature change. S.I. unit: J kg⁻¹.
   2. B. The heat energy needed to raise the temperature of 1 kg of ice by 1°C. S.I. unit: J kg⁻¹ °C⁻¹.
   3. C. The heat energy released when 1 kg of water freezes at 0°C. S.I. unit: J.
   4. D. The temperature change when 1 kg of ice melts at 0°C. S.I. unit: °C.
   [1]
5. 5.
   272 calories of heat is required to heat $0.02\,\mathrm{kg}$ of a metal of specific heat capacity $170\,\mathrm{cal}\,\mathrm{kg}^{-1\,^{\circ}\mathrm{C}^{-1}}$ to a temperature $T$. If the initial temperature of the metal is $20^{\circ}\mathrm{C}$, calculate the final temperature $T$.

   1. A. $25^{\circ}\mathrm{C}$
   2. B. $75^{\circ}\mathrm{C}$
   3. C. $100^{\circ}\mathrm{C}$
   4. D. $90^{\circ}\mathrm{C}$
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6. 6.
   What is the S.I. unit of heat?

   1. A. calorie
   2. B. joule (J)
   3. C. watt
   4. D. kelvin
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7. 7.
   You are required to make a water bath of $50\,\mathrm{kg}$ at $45^{\circ}\mathrm{C}$, by mixing hot water at $90^{\circ}\mathrm{C}$, with cold water at $20^{\circ}\mathrm{C}$. Calculate the amount of hot water required. Hint: Let amount of hot water $= x$\nHence, Amount of cold water $= (50 - x)\,\mathrm{kg}$

   1. A. $7.871\,\mathrm{kg}$
   2. B. $27.871\,\mathrm{kg}$
   3. C. $17.857\,\mathrm{kg}$
   4. D. $37.871\,\mathrm{kg}$
   [1]
8. 8.
   The same amount of heat is supplied to two liquids A and B. Liquid A shows a greater rise in temperature. What can you conclude about the heat capacity of A compared to that of B?

   1. A. The heat capacity of A is greater than that of B.
   2. B. The heat capacity of A is less than that of B.
   3. C. The heat capacity of A is equal to that of B.
   4. D. The heat capacity of A is unrelated to the temperature rise.
   [1]
9. 9.
   A certain amount of heat Q warms 1 g of material X by 3°C and 1 g of material Y by 4°C. Which material has a higher specific heat capacity?

   1. A. Material Y, because it shows a larger temperature change.
   2. B. Material X, because it shows a smaller temperature change.
   3. C. Both have the same specific heat capacity.
   4. D. Cannot be determined without knowing Q.
   [1]
10. 10.
    In winter, a farmer watered his fields the night before a forecast of 'severe frost' to prevent frost damage to his crops. Why did he water his fields?

    1. A. Water absorbs heat from the crops as it evaporates, lowering their temperature.
    2. B. Water releases latent heat as it freezes, preventing the crops' temperature from dropping below $0^{\circ}\mathrm{C}$.
    3. C. Water acts as an insulator, trapping heat in the soil and preventing frost formation.
    4. D. Water increases the humidity, which prevents frost from forming on the crops.
    [1]
11. 11.
    Which of the following best explains why the base of a cooking pan is made thick?

    1. A. A thick base increases the thermal capacity, allowing even heat distribution at lower temperatures.
    2. B. A thick base reduces the weight of the pan, making it easier to handle.
    3. C. A thick base prevents the pan from conducting heat to the food.
    4. D. A thick base makes the pan more durable and resistant to scratches.
    [1]
12. 12.
    What is the principle of the method of mixtures, what other name is it known by, and which fundamental law underlies this principle?

    1. A. Heat lost by the hot body equals heat gained by the cold body; principle of calorimetry; law of conservation of energy.
    2. B. Heat lost by the cold body equals heat gained by the hot body; principle of thermal equilibrium; law of entropy.
    3. C. Heat transfer depends on mass and temperature difference; principle of thermodynamics; Newton's law of cooling.
    4. D. Heat energy is conserved only in isolated systems; principle of heat exchange; law of specific heat capacity.
    [1]
13. 13.
    What property of water makes it an effective coolant?

    1. A. Water has a high specific heat capacity, allowing it to absorb large amounts of heat without a significant rise in temperature.
    2. B. Water has a low boiling point, which helps it evaporate quickly and cool surfaces.
    3. C. Water is a good conductor of heat, enabling it to transfer heat rapidly.
    4. D. Water has a high density, which allows it to carry more heat per unit volume.
    [1]
14. 14.
    Which of the following is NOT a reason why copper is preferred over other metals for making calorimeters?

    1. A. Copper is a good conductor and quickly attains the temperature of its contents.
    2. B. Copper has a low specific heat capacity, minimizing heat absorption from the system.
    3. C. Copper is highly resistant to corrosion and chemical reactions.
    4. D. Copper's thermal conductivity ensures rapid temperature equilibrium.
    [1]
15. 15.
    Land and sea breezes are formed in coastal regions because:

    1. a. land has very high specific heat capacity than the water.
    2. b. sea water cools the cooler regions.
    3. c. water has very high specific heat capacity than the land.
    4. d. all the above.
    [1]
16. 16.
    How is the heat capacity of a body related to the specific heat capacity of its substance?

    1. A. Heat capacity is the product of the body's mass and its specific heat capacity.
    2. B. Heat capacity is the ratio of the body's mass to its specific heat capacity.
    3. C. Heat capacity is independent of the body's mass and specific heat capacity.
    4. D. Heat capacity is the sum of the body's mass and its specific heat capacity.
    [1]
17. 17.
    In a central heating system, steam enters a radiator pipe at 100°C and water leaves at 100°C. Can this radiator pipe heat a room, and why?

    1. A. No, because there is no temperature difference to transfer heat.
    [1]
18. 18.
    50 g of ice at 0°C is added to 300 g of a liquid at 30°C. What will be the final temperature of the mixture when all the ice has melted? The specific heat capacity of the liquid is 2.65 J g⁻¹ °C⁻¹ while that of water is 4.2 J g⁻¹ °C⁻¹. Specific latent heat of fusion of ice = 336 J g⁻¹.

    1. A. 5°C
    2. B. 7°C
    3. C. 10°C
    4. D. 12°C
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19. 19.
    What mass of a liquid A of specific heat capacity 0.84 J g⁻¹ K⁻¹ at a temperature 40°C must be mixed with 100 g of a liquid B of specific heat capacity 2.1 J g⁻¹ K⁻¹ at 20°C, so that the final temperature of the mixture becomes 32°C?

    1. A. 125 g
    2. B. 250 g
    3. C. 375 g
    4. D. 500 g
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20. 20.
    What is the effect of an increase in pressure on the melting point of ice and the boiling point of water?

    1. A. Melting point of ice increases; boiling point of water decreases.
    2. B. Melting point of ice decreases; boiling point of water increases.
    3. C. Both melting point of ice and boiling point of water increase.
    4. D. Both melting point of ice and boiling point of water decrease.
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