Heat and Mass Transfer MCQs

Question 1

Stefan Boltzmann law is applicable for heat transfer by

Accepted Answer

Radiation

Answer

Conduction

Answer

Convection

Answer

Conduction and radiation combined

Question 2

A non-dimensional number generally associated with natural convection heat transfer is

Accepted Answer

Grashoff number

Answer

Nusselt number

Answer

Weber number

Answer

Prandtl number

Question 3

The unit of overall coefficient of heat transfer is

Accepted Answer

kcal/m2 hr °C

Answer

kcal/m2

Answer

kcal/hr °C

Answer

kcal/m hr °C

Question 4

Unit of thermal conductivity in S.I. units is

Accepted Answer

Option (B) and (C) above

Answer

J/m2 sec

Answer

J/m °K sec

Answer

W/m °K

Question 5

According to Wien's law, the wavelength corresponding to maximum energy is proportion to

Accepted Answer

Absolute temperature (T)

Answer

f

Answer

t

Answer

None of these

Question 6

Which of the following has least value of conductivity?

Accepted Answer

Air

Answer

Glass

Answer

Water

Answer

Plastic

Question 7

According to Prevost theory of heat exchange

Accepted Answer

All bodies above absolute zero emit radiation

Answer

It is impossible to transfer heat from low temperature source to high temperature source

Answer

Heat transfer by radiation requires no medium

Answer

Heat transfer in most of the cases takes place by combination of conduction, convection and radiation

Question 8

Conduction is a process of heat transfer

Accepted Answer

From one particle of the body to another without the actual motion of the particles

Answer

From one particle of the body to another by the actual motion of the heated particles

Answer

From a hot body to a cold body, in a straight line, without affecting the intervening medium

Answer

None of the above

Question 9

According to Dalton's law of partial pressures, (where pb = Barometric pressure, pa = Partial pressure of dry air and pv = Partial pressure of water vapour)

Accepted Answer

Pb = pa + pv

Answer

Pb = pa - pv

Answer

Pb = pa × pv

Answer

$${	ext{Pb}} = \frac{{{	ext{pa}}}}{{{	ext{pv}}}}$$