Heat Transfer MCQs

Question 1

jH factor for heat transfer depends upon the __________ number.

Accepted Answer

Reynolds

Answer

Biot

Answer

Nusselt

Answer

Prandtl

Question 2

The dimensionless group in mass transfer that is equivalent to Prandtl number in heat transfer is

Accepted Answer

Schmidt number

Answer

Nusselt number

Answer

Sherwood number

Answer

Stanton number

Question 3

With increase in porosity, the thermal conductivity of a solid substance

Accepted Answer

Decreases

Answer

Increases

Answer

Remains unchanged

Answer

May increase or decrease; depends on the solid

Question 4

'Duhring's plot' is of use in

Accepted Answer

Evaporation

Answer

Extractive distillation

Answer

Leaching

Answer

Absorption

Question 5

Heat exchangers operating, when the asymptotic range is reached,

Accepted Answer

Results in making part of the heating surface inactive

Answer

Provide very large heat transfer co-efficient

Answer

Results in abruptly increased velocity

Answer

None of these

Question 6

In natural convection heat transfer, the correlating parameter is the

Accepted Answer

Grashoff number

Answer

Graetz number

Answer

Eckert number

Answer

Bond number

Question 7

Stefen's block body radiation law can also be derived from __________ law.

Accepted Answer

Planck's

Answer

Kirchoffs

Answer

Fourier's

Answer

None of these

Question 8

What is the emissivity of a black body?

Accepted Answer

1

Answer

0

Answer

0.9

Answer

0.5

Question 9

Pick out the wrong statement.

Accepted Answer

Orifice baffles are never used in a shell and tube heat exchanger

Answer

Pressure drop on the shell side of a heat exchanger depends upon tube pitch also

Answer

In a horizontal tube evaporator, surface blanketing by air is avoided

Answer

Split ring type and pull through type floating heads are two commonly used floating heads is heat exchangers