K/h0
2K/h0
hi/K
2hi/K
✅ The correct answer is option A.
Heat Transfer MCQs
Fresh orange juice contains 12% (by weight) solids and the rest water 90% of the fresh juice is sent to an evaporator to remove water and subsequently mixed with the remaining 10% of fresh juice. The resultant product contains 40% solids. The kg of water removed from 1 kg fresh juice is
0.4
0.5
0.6
0.7
✅ The correct answer is option D.
Heat sensitive materials can be concentrated in an evaporator employing
Vacuum
High pressure
High residence time
None of these
✅ The correct answer is option A.
A hot body will radiate heat most rapidly, if its surface is
White & rough
Black & rough
White & polished
Black & polished
✅ The correct answer is option B.
The characteristic dimensionless groups for heat transfer to a fluid flowing through a pipe in laminar flow are
Re.Gz
Nu, Pr
Nu, Pr, Re
Nu, Gz
✅ The correct answer is option D.
Heat flux is the time rate of heat transfer per unit
Length
Area
Volume
None of these
✅ The correct answer is option B.
A graph between __________ is called Wilson plot.
1/U Vs . 1/v0.8
1/v0.8 Vs . U
V0.8 Vs . U
1/U Vs . 1/V
✅ The correct answer is option A.
Open pan evaporators are preferred to be used, when the solution to be concentrated is
Scaling
Highly viscous
Corrosive
Salty
✅ The correct answer is option B.
For a liquid in laminar flow through a very long tube, when the exit fluid temperature approaches the wall temperature, the equation to be used is
Nu = 0.023 Re0.8 . Pr0.4
Nu = Gz
Nu = Gz
Nu = 2Gz0.5
✅ The correct answer is option C.
In pipe flow, heat is transferred from hot wall to the liquid by
Conduction only
Forced convection only
Forced convection and conduction
Free and forced convection
✅ The correct answer is option C.