1673. Heat exchanger tubes are never made of
Plain carbon steel
Stainless steel
Lead
Copper
✅ The correct answer is option C.
1676. Boiling point elevation of a solution of NaOH
Increases rapidly with temperature rise
Is almost independent of temperature
Is almost independent of pressure
Both B and C
✅ The correct answer is option D.
1643. 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.
1646. Film condensation is promoted on a/an __________ surface.
Oily
Coated
Clean & smooth
Dirty
✅ The correct answer is option C.
1649. 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.
1617. The capacity of double-effect evaporator is less than half of the capacity of two single effects, each of which is operating over same terminal temperature difference, when the
Solution has an elevation of boiling point
Evaporators operate under vacuum
Evaporators opreate at atmospheric pressure
None of these
✅ The correct answer is option A.
1620. Heat exchangers operating, when the asymptotic range is reached,
Provide very large heat transfer co-efficient
Results in making part of the heating surface inactive
Results in abruptly increased velocity
None of these
✅ The correct answer is option B.
1623. Nusselt number for full developed, laminar, constant property flow in a pipe at uniform heat flux is
0.72
4.364
18
83
✅ The correct answer is option B.