An oily surface
When both the steam and the tube are clean
Only in presence of air
None of these
✅ The correct answer is option A.
Heat Transfer MCQs
Prandtl number for most of dry gases is about
0.001
0.72
70
150
✅ The correct answer is option B.
The number of kg vaporised per kg of steam fed to the evaporator is defined as
Capacity
Rate of evaporation
Economy
Rate of vaporisation
✅ The correct answer is option C.
Mechanical recompression evaporation is used in the production of
Alcohol
Distilled water
Salt
Fruits jam
✅ The correct answer is option B.
Heat flux, as defined in heat flow is analogous to __________ in electricity flow.
Current
Voltage
Resistance
None of these
✅ The correct answer is option A.
With increase in temperature, the thermal conductivity of steel
Increases
Decreases
Remains unchanged
Increases exponentially
✅ The correct answer is option B.
A cube, sphere & a thin circular plate (all having same mass and made of same material) are all heated to 300°C and allowed to cool in natural air. Which one will cool the slowest ?
Cube
Plate
Sphere
All of the above
✅ The correct answer is option C.
Circulation pump is located below the evaporater to
Avoid cavitation
Avoid frequent priming
Create more suction head
None of these
✅ The correct answer is option C.
For a given ambient air temperature with increase in the thickness of insulation of a hot cylinderical pipe, the rate of heat loss from the surface would
Decrease
Increase
First decrease and then increase
First increase and then decrease
✅ The correct answer is option D.
In a heat exchanger, floating head is provided to
Facilitate cleaning of the exchanger
Increase the heat transfer area
Relieve stresses caused by thermal expansion
Increase log mean temperature gradient
✅ The correct answer is option C.