Available Answers

1. 1.

   State whether the following statements are true or false. Rewrite the correct statement if it is false.

   1. Boiling takes place at all temperatures.
   2. We feel refreshed under a tree during summers.
   3. Evaporation takes place over the entire mass of the liquid.,
   4. Boiling water at 100°C produces more severe burns than at 100°C.
   5. When heat energy is supplied to a substance, the intermolecular space increases.
   6. According to the principle of calorimetry, heat lost by the hot object is equal to the heat gained by the cold object. when they are in contact.
   7. In cold countries, juice bottles are kept in water to avoid their freezing.
   8. The climate on hill station remains moderate due to land breeze and mountain breeze.
   9. The unit of specific heat capacity is J kg-1°C^-1.
   10. The process of a gas converting into solid directly is called sublimation.
2. 2.

   Fill in the blanks :

   1. Water is used in a hot water bottle for ________________.
   2. Water is used as ________________ in machines.
   3. ________________ has highest specific heat capacity among liquids.
   4. The cold air moving from sea to land is called ________________.
   5. ________________ is a process just reverse of melting.
   6. ________________ is process that involves direct conversion of a solid into gas on heating.
   7. The amount of heat required by a unit mass of a substance to change its state without any change in temperature is called ________________.
   8. The SI unit of specific heat capacity is ________________.
   9. The temperature at which a solid converts into a liquid is called its ________________.
   10. Evaporation occurs only from the ________________ of the liquid.
3. 3.

   Tick the appropriate answer:

   (a) The coolant used in a car engine is

   1. alcohol
   2. benzene
   3. water
   4. petrol

   (b) The specific heat capacity of water is

   1. 4250 J kg^-1°C^-1
   2. 4200 J J kg^-1°C^-1
   3. 5000 J kg^-1°C^-1
   4. 4250 J kg^-1°C^-1

   (c) The amount of heat required to raise the temperature through 1°C is called

   1. thermal energy
   2. calorie
   3. heat capacity
   4. specific heat capacity

   (d) During land breeze, there is a fall of pressure over the surface of

   1. land
   2. water (sea)
   3. air
   4. none of the above

   (e) The temperature at which a liquid gets converted into its vapour state is called its

   1. melting point
   2. boiling point
   3. dew point
   4. freezing point

   (f) Rapid conversion of water into steam is an example of

   1. evaporation
   2. freezing
   3. melting
   4. vapourisation

   (g) Evaporation takes place from

   1. surface of liquid
   2. throughout the liquid
   3. from the mid-portion of the liquid
   4. bottom of liquid

   (h) Boiling takes place from

   1. surface of liquid
   2. throughout the liquid
   3. from the mid-portion of liquid
   4. none of the above

   The unit of specific latent heat is

   1. J kg^-1°C^-1
   2. J/kg°C Cal
   3. J/kg
   4. None of these

   (j) The unit of specific heat capacity is

   1. J kg^-1°C^-1
   2. J/kg°C Cal
   3. J/kg
   4. None of these
4. 4.

   Match the following:

   Specific latent heat of vapourisation of water Specific latent heat of fusion of ice Boiling point of water Melting point of ice Specific heat capacity of iron

   483 J kg-1°C-1 100°C 0°C 2260000 J/kg 336000 J/kg

5. 5.

   Define one kilocalorie. How is it related to Joules?

6. 6.

   Express 336000 J in calories.