32.

38.

34.

38.

87.

Which of the following statements is not true?
(5) The coefficient of performance ല്‌ refrigerator 1s generally greater than one

18) The coefficient of performance of a heat pump equals the reciprocal of thermal
efficiency of an engine working with in the same temperature limits

(C) The horse power per ton of refrigeration equals 4.75 times the coefficient of
performance

(D) The refrigerating effect corresponding 10 one ton of refrigeration is nearly equal to
210 kJ/min

Solar energy can be directly used in
(A) air refrigeration system
(B) jet refrigeration system
(0 vapour compression refrigeration system
(D) vapour absorption refrigeration system

Choose the false statement
(ಗ) thermal conductivity is always higher in the purest form of metal
(B) heat treatment causes considerable variation in thermal conductivity

(C) thermal conductivity of a damp material is considerably higher than the thermal
conductivity of the dry material and water taken individually

(D) thermal conductivity decreases with increase in the density of the substance

Fins are usually provided to a heat exchanger surface in order to augment heat transfer by
increasing the

(ಗಿ) heat transfer coefficient (18) surface area
(C) turbulence level ‏٠‎ (D) temperature difference

Transient conduction means
(ಯ) very little heat transfer
(B) heat transfer for a short time
(C) heat transfer with a very small temperature difference
(D) eonduction when the temperature at a point varies with time

Isothermal efficiency of a compressor is defined 88 the ratio of
(ಗೆ) volume of free air delivered per stroke to the swept volume of the piston

(ए) indicated power to shaft power of the motor of engine required to drive the
compressor

(0 adiabatic power to the power required to drive the compressor

(D) isothermal work to the actual work required to compress the air for the same
pressure ratio

7 090/2016
17.10]