Multiple Choice Questions (MCQ) with answers on Refrigeration and Air conditioning

31-The operation theatre in a hospital is to be air conditioned. Suggest the percentage of outside air being circulated in the theatre:

(A) zero

(B) 20

(C) 50

(D) 100


32-Which of the following refrigerant has the lowest boiling point?

(A) carbon dioxide

(B) Ammonia

(C) Hydrogen

(D) Freon 12


33-Auto defrost is operated by

(A) Evaporator fan

(B) Thermostat

(C) Timer watch

(D) Heating element


34-The absolute zero temperature corresponds on the condition when

(A) all the substances exit only as solids

(B) volume of a gas reduces to zero

(C) kinetic energy of gas molecules becomes zero

(D) no pressure is exerted by the gas


35-Sum of atmospheric pressure and gauge pressure is called

(A) Total pressure

(B) Absolute pressure

(C) Normal pressure

(D) Natural pressure


36-The effectiveness of the cooling tower is dependent on:

(A) dry bulb temperature of the air

(B) direction of the flow of air

(C) wet bulb temperature of the air

(D) none of the above


37-One micron of vaccum is equal to

(A) 0.1 MM Hg

(B) 0.01 MM Hg

(C) 0.001 MM Hg

(D) 0.0001 MM Hg


38-In a flooded evaporator which of the following types of expansion device is employed?

(A) float valve

(B) capillary tube

(C) automatic expansion valve

(D) thermostatic expansion valve


39-In a thermal electric expansion valve which senses the suction temperature is

(A) Transformer

(B) Thermister

(C) Thermostat

(D) Rheostat


40-The specific humidity is the mass of water vapour present in

(A) 1 kg of dry air

(B) 1 m3 of dry air

(C) 1 m3 of wet air

(D) 1 kg of wet air



31-(D), 32-(C), 33-(A), 34-(C), 35-(B), 36-(C), 37-(C), 38-(A), 39-(B), 40-(D)