Heat Transfer - Study Mode
[#481] Fluid motion in the natural convection heat transfer between a solid surface and a fluid in contact with it, results from the
Correct Answer
(B) Temperature gradient produced due to density difference
Explanation
Solution: In natural convection heat transfer, fluid motion is driven by the temperature gradient produced due to density difference. As a fluid near a heated surface becomes warmer, it tends to rise due to a decrease in density. Conversely, the cooler fluid descends. This creates a continuous circulation known as natural convection currents. Therefore, the correct answer is Option B: Temperature gradient produced due to density difference .
[#482] For a multipass shell and tube heat exchanger, the LMTD correction factor is always
Correct Answer
(C) < 1
[#483] The energy radiated from a surface Q at absolute temperature T is related as
Correct Answer
(B) Q ∝ T 4
[#484] At constant temperature, the thermal conductivities of gases __________ with rise in pressure.
Correct Answer
(A) Decrease
[#485] The film co-efficient is decreased due to the presence of non-condensing gases in the vapors. The film co-efficient of superheated vapor as compared to that of saturated vapor is
Correct Answer
(C) Some