Topicwise - Heat and Temperature

1. Which of the following is the fastest process of heat transfer?

  1. conduction
  2. convection
  3. radiation
  4. insolation

2. The factors directly proportional to the amount of heat conducted through a metal rod are -

  1. Time of flow of Heat
  2. Area of cross section
  3. Temperature gradient
  4. All the above

3. 1 gm of ice at 0° C is mixed with 1 gm of steam at 100° C. After thermal equilibrium, the temperature of the mixture is

  1. 0° C
  2. 50° C
  3. 80° C
  4. 100° C

4. What would be the thermal resistance of an ideal conductor?

  1. Zero
  2. One
  3. Infinity
  4. Ten

5. Why does the bottom of a lake not freeze in severe winter even when the surface is all frozen?

  1. The water has large specific heat
  2. The conductivity of ice is low
  3. The water has large latent heat of fusion
  4. The temperature of the earth at the bottom of the lake is high.

6. A cooking pot is coated black because -

  1. black substances absorb more heat
  2. black substances reflect more heat
  3. black surfaces are easier to clean
  4. the material of the pot would not be damaged

7. Specific heat is -

  1. the specific temperature at which the substance is in solid state.
  2. the energy needed to increase the temperature of 1 gram of a substance by 1 degree Celsius.
  3. the amount of heat conducted in 1 minute.
  4. the heat needed to increase the temperature of 1 gallon of water by 1 degree Fahrenheit.

8. How will a metal container full of hot water in vaccum lose heat?

  1. by conduction
  2. by convection
  3. by radiation
  4. will stay hot for ever

9. A block of ice

  1. cannot radiate heat
  2. can radiate heat but cannot absorb heat
  3. can absorb heat but cannot radiate heat
  4. can radiate as well as absorb heat

10. As a solid undergoes a phase change to a liquid state, it

  1. releases heat while remaining at a constant temperature.
  2. absorbs heat while remaining at a constant temperature.
  3. releases heat as the temperature decreases.
  4. absorbs heat as the temperature increases.

11. A cup of hot tea on a metal table in a room loses heat by

  1. Conduction
  2. Convection
  3. Radiation
  4. All the above

12. Which among the following is true of a sphere, a cube and circular plate of same material and same mass heated to same temperature?

  1. Sphere cools the slowest
  2. Circular plate cools the fastest
  3. Cube cools the fastest
  4. Circular plate cools the slowest

13. At what temperature are the Celsius and Fahrenheit equal?

  1. + 40o
  2. - 40o
  3. - 0o
  4. + 100o

14. What would happen to a hole in a metal sheet when the sheet is heated?

  1. It decreases in size
  2. It increases in size
  3. No change is seen
  4. First increases and then decreases

15. Which of the following is equivalent of a calorie?

  1. the specific heat of water.
  2. the energy needed to increase the temperature of 1 gram of water 1 degree Celsius.
  3. equivalent to a little over 4 joules of mechanical work.
  4. all of the above.

16. In which of the following processes of heat transfer no medium is required?

  1. Conduction
  2. Convection
  3. Radiation
  4. All

17. In which of the following processes is heat transferred directly from molecule to molecule?

  1. conduction
  2. convection
  3. radiation
  4. all of the above

18. When a solid, liquid, or a gas changes from one physical state to another, the change is called

  1. melting
  2. enthalpy
  3. a phase change
  4. sublimation

19. The surface which radiates more heat at a given temperature is

  1. Black and Polished
  2. White and polished
  3. White and Rough
  4. Black and Rough

20. Compared to warm air, cool air can hold

  1. more water vapour
  2. less water vapour
  3. the same amount of water vapour
  4. temperature is unimportant here

21. The change of state directly from solid to gas is called

  1. evaporation
  2. sublimation
  3. condensation
  4. deposition