451. The ratio of velocity head to tube side return loss in case of a multipass shell and tube heat exchanger is
2
1-Feb
4
1-Apr
✅ The correct answer is option D.
Heat Transfer MCQs
452. The interchange factor for radiation heat transfer from surface ‘x’ to surface ‘y’ in case of an infinite parallel planes with emis-sivities εx & εy is given by
Εx + εy
Εx . εy
1/εx + 1/εy
(εx + εy)/(εx + εy – εx . εy)
✅ The correct answer is option D.
453. With increase in temperature, the total emissivity of conductors
Increases
Decreases
Remains same
Decreases linearly
✅ The correct answer is option A.
454. A __________ surface has the maximum thermal emissivity out of the following.
Black & smooth
Black & rough
White & smooth
White & rough
✅ The correct answer is option B.
455. Economy of a multiple effect evaporator depends upon the
Heat balance consideration
Rate of heat transfer
Both A and B
Neither A nor B
✅ The correct answer is option A.
456. Radiator of an automobile engine is a __________ type of heat exchanger.
Co-current
Cross-current
Counter-current
Direct contact
✅ The correct answer is option D.
457. If heat transfer rate varies with the time, it is termed as
Forced convection
Steady state conduction
Monochromatic radiation
None of these
✅ The correct answer is option D.
458. (Cp . μ)/K is termed as the __________ number.
Grashoff
Nusselt
Prandtl
Stanton
✅ The correct answer is option C.
459. The advantage of using a 1 – 2 shell and tube heat exchanger over a 1 – 1 shell and tube heat exchanger is
Lower tube side pressure drop
Lower shell side pressure drop
Higher tube side heat transfer co-efficient
Higher shell side heat transfer co-efficient
✅ The correct answer is option C.
460. For __________ Prandtl number values, the heat conduction will be negligible in the buffer zone.
Extremely low
Low
High
No
✅ The correct answer is option C.