431. It is not preferable to use superheated steam in evaporators, because of its very
High temperature
High pressure
Low film co-efficient
None of these
✅ The correct answer is option C.
Heat Transfer MCQs
432. Thermal conductivities of most of the liquids __________ with rise in temperature.
Increases
Decreases
Remains unchanged
May increase or decrease; depends on the liquid
✅ The correct answer is option B.
433. Which of the following has the highest thermal conductivity?
Brick
Air
Water
Silver
✅ The correct answer is option D.
434. __________ chart is known as transient heat conduction chart.
Dirhing’s
Heisler’s
Mollier’s
Cox
✅ The correct answer is option A.
435. Film condensation is promoted on a/an __________ surface.
Oily
Coated
Clean & smooth
Dirty
✅ The correct answer is option C.
436. Removal of __________ heat is involved in the condensation of a vapor under saturated conditions.
Super
Sensible
Latent
Both B & C
✅ The correct answer is option B.
437. The statement that “maximum wavelength of radiation is inversly proportional to the temperature” is __________ law.
Stefan-Boltzman’s
Planck’s
Wien’s displacement
None of these
✅ The correct answer is option C.
438. Which type of heat exchanger is preferred for heavy heat loads?
Double pipe
Plate fine
Series and parallel set of shell and tube
None of these
✅ The correct answer is option C.
439. For flow over a flat plate, the ratio of thermal boundary layer thickness, ‘xt’ and hydrodynamic boundary layer thickness ‘x’ is equal to (where, NPr = Prandtl number)
NPr
NPr1/3
NPr-1
NPr-1/3
✅ The correct answer is option B.
440. Heat transfer efficiency leading of energy conservation in a heat exchanger can be achieved by
Keeping the heat transfer surface clean
Enhancing the fluid pumping rate
Increasing the tube length
None of these
✅ The correct answer is option A.