281. The wave length of the radiation emitted depends only on the temperature and is independent of the material of the body.
TRUE
FALSE
✅ The correct answer is option A.
Heat Transfer, Refrigeration and Air Conditioning MCQs
282. In counter-current flow heat exchanger, the logarithmic temperature difference between the fluids is __________ as compared to parallel flow heat exchanger.
same
less
greater
✅ The correct answer is option C.
283. The transfer of heat from one body to another takes place only when there is a temperature difference between the bodies.
Yes
No
✅ The correct answer is option A.
284. A low wet bulb temperature indicates very __________ humidity.
low
high
✅ The correct answer is option A.
285. The ratio of Nusselt number and the product of Reynold’s number and Prandtl number is equal to
Stanton number
Biot number
Peclet number
Grashoff number
✅ The correct answer is option A.
286. The reciprocating refrigerant compressors are very suitable for
small displacements and low condensing pressures
large displacements and high condensing pressures
small displacements and high condensing pressures
large displacements an
✅ The correct answer is option C.
287. The transfer of heat by molecular collision is smallest in
solids
liquids
gases
none of these
✅ The correct answer is option C.
288. The rate of heat flow through a body is . The term is known as temperature gradient.
Yes
No
✅ The correct answer is option A.
289. An electric cable of aluminium conductor (k = 240 W/mK) is to be insulated with rubber (k = 0.15 W/mK). The cable is to be located in air (h = 6 W/m2). The critical thickness of insulation will be
25 mm
40 mm
160 mm
800 mm
✅ The correct answer is option A.
290. During humidification process, dry bulb temperature
remains constant
increases
decreases
✅ The correct answer is option A.