21. The heating of air, without any change in its specific humidity, is known as sensible heating.
TRUE
FALSE
✅ The correct answer is option A.
Heat Transfer, Refrigeration and Air Conditioning MCQs
22. In a psychrometric chart, specific humidity (moisture content) lines are
vertical and uniformly spaced
horizontal and uniformly spaced
horizontal and non-uniformly spaced
curved lines
✅ The correct answer is option B.
23. The capacity of the cooling tower and spray ponds __________ as the wet bulb temperature of air decreases.
increases
decreases
✅ The correct answer is option A.
24. The lowest thermal diffusivity is of
iron
lead
aluminium
rubber
✅ The correct answer is option D.
25. In case of sensible heating of air, the coil efficiency is given by (where B.P.F. = By-pass factor)
B.P.F. – 1
1 – B.P.F.
1 + B.RF.
✅ The correct answer is option B.
26. In figure shown, E is a heat engine with efficiency of 0.4 and R is a refrigerator. It is given that Q2 + Q4 = 3Q1. The C.O.P. of the refrigerator is
2.5
3
4
5
✅ The correct answer is option D.
27. In a domestic refrigerator, a capillary tube controls the flow of refrigerant from the
expansion valve to the evaporator
evaporator to the thermostat
condenser to the expansion valve
condenser to the evapo
✅ The correct answer is option D.
28. The thermostatic expansion valve is used in __________ type of evaporators.
flooded
DX coil
dry
✅ The correct answer is option C.
29. The material of pipe lines for a system using freon as a refrigerant should be
brass
copper
steel
aluminium
✅ The correct answer is option B.
30. The value of the wave length for maximum emissive power is given by
Kirchhoff’s law
Stefan’s law
Wein’s law
Planck’s law
✅ The correct answer is option C.