Mechanical Engineering Principles

220 MECHANICAL ENGINEERING PRINCIPLES

(a) 500 kJ (b) 0.5 kJ

(c) 2 J (d) 250 kJ

6. The heat energy required to change 1 kg
   of a substance from a liquid to a gaseous
   state at the same temperature is called:
   (a) specific heat capacity
   (b) specific latent heat of vaporisation
   (c) sensible heat
   (d) specific latent heat of fusion


7. The temperature of pure melting ice is:

(a) 373 K (b) 273 K

(c) 100 K (d) 0 K

8. 1.95 kJ of heat is required to raise
   the temperature of 500 g of lead from
   15 °C to its final temperature. Taking
   the specific heat capacity of lead to be
   130 J/(kg°C), the final temperature is:

(a) 45°C (b) 37.5°C

(c) 30°C (d) 22.5°C

9. Which of the following temperatures is
   absolute zero?

(a) 0°C(b)− 173 °C

(c)− 273 °C(d)− 373 °C

10. When two wire of different metals are
    twisted together and heat applied to the
    junction, an e.m.f. is produced. This
    effect is used in a thermocouple to
    measure:

(a) e.m.f. (b) temperature

(c) expansion (d) heat

11. Which of the following statements is
    false?
    (a) − 30 °C is equivalent to 243 K

(b) Convection only occurs in liquids

and gases

(c) Conduction and convection cannot

occur in a vacuum

(d) Radiation is absorbed by a silver

surface

12. The transfer of heat through a substance
    by the actual movement of the particles
    of the substance is called:

(a) conduction (b) radiation

(c) convection (d) specific heat capacity

13. Which of the following statements is
    true?

(a) Heat is the degree of hotness or

coldness of a body.

(b) Heat energy that flows to or from

a substance while the temperature

remains constant is called sensi-

ble heat.

(c) The unit of specific latent heat of

fusion is J/(kg K).

(d) A cooker-grill is a practical appli-

cation of radiation.