Black painted bodies only
All bodies
Polished bodies only
A black body
✅ The correct answer is option B.
Heat Transfer MCQs
232. For a multipass shell and tube heat exchanger, the LMTD correction factor is always
1
> 1
< 1
Between 1 & 2
✅ The correct answer is option C.
233. Choose the correct equation.
Nu = (Re) (Pr) (Gz)
Nu = (Re) (Pr) (St)
Nu = (Re)(Pr)
Nu = (Pr)(St)
✅ The correct answer is option B.
234. Radiant energy received by a body is proportional to (where, d = the distance between the object emitting radiation and that receiving it.)
√d
d
d2
d1.5
✅ The correct answer is option C.
235. In a single effect evaporator, the economy is
1
< 1
> 1
None of these
✅ The correct answer is option B.
236. Condensing film co-efficient for steam on horizontal tubes ranges from 5000 to 15000 Kcal/hr.m² .°C. Condensation of vapor is carried out inside the tube in a shell and tube heat exchanger, when the
Higher condensing film co-efficient is desired
Condensate is corrosive in nature
Lower pressure drop through the exchanger is desired
Temperature of the incoming vapor is very high
✅ The correct answer is option B.
237. A sphere of radius ‘R₁’ is enclosed in a sphere of radius ‘R₂’. The view (or shape) factor for radiative heat transfer of the outer sphere with respect to the inner sphere is
0
R₂/(R₁+R₂)
1
(R₁/R₂)2
✅ The correct answer is option B.
238. Trap is used to remove __________ from steam pipe lines.
Steam
Condensate
Non-condensables
None of these
✅ The correct answer is option B.
239. Rate of heat transfer by vaporisation from pools of water is affected by the
Nature of heating surface and distribution of bubbles
Surface tension of water
Viscosity of water
All of the above
✅ The correct answer is option D.
240. Maximum heat transfer rate is achieved in __________ flow.
Co-current
Counter-current
Turbulent
Laminar
✅ The correct answer is option C.