Condensation of the saturated vapor on a cold surface
Concentration of a corrosive solution by evaporation
Heat transfer between two highly viscous liquids
Boiling of a liquid on a hot surface
✅ The correct answer is option D.
Heat Transfer MCQs
342. For the same heat load and mass flow rate in the tube side of a shell and tube heat exchanger, one may use multipass on the tube side, because it
Decreases the pressure drop
Decreases the outlet temperature of cooling medium
Increases the overall heat transfer coefficient
None of these
✅ The correct answer is option C.
343. The sum of reflectivity and absorptivity for an opaque body is equal to
0.5
1
0
2
✅ The correct answer is option B.
344. Dietus-Boelter equation used for the determination of heat transfer co-efficient is valid
For fluids in laminar flow
For fluids in tubulent flow
When Grashhoff number is very important
For liquid metals
✅ The correct answer is option B.
345. At what value of Prandtl number, conduction is negligible in the turbulent core of a fluid flowing through a heated pipe?
0.5
< 0.5
> 0.6
< 0.1
✅ The correct answer is option C.
346. Which of the following is the most controlling factor for the rate of bubble detachment from the hot solid surface?
Liquid density
Liquid viscosity
Hot surface temperature
Interfacial tension
✅ The correct answer is option D.
347. Among liquids, water has a comparatively high value of thermal conductivity, due to its
Low density
High viscosity
Partial ionisation
Dense structure
✅ The correct answer is option C.
348. Fouling factor for a heat exchanger is given by (where, U₁ = heat transfer co-efficient of dirty surface U₂ = heat transfer co-efficient of clean surface)
U₁ – U₂
1/U₁ – 1/U₂
1/U₂ – 1/U₁
U₂ – U₁
✅ The correct answer is option B.
349. The equivalent diameter for pressure drop is __________ that for heat transfer.
Smaller than
Greater than
Equal to
Not related with
✅ The correct answer is option A.
350. Steam consumption in kg/hr in case of an evaporator is given by (where, C & E are capacity the economy of the evaporator respectively)
C/E
E/C
CE
1/CE
✅ The correct answer is option A.