Heat Transfer MCQs

Question 1

According to planck's law, the wavelength corresponding to the maximum energy is proportional to

Accepted Answer

T4

Answer

Absolute temperature T

Answer

T2

Answer

1/T

Question 2

When heat is transferred form hot body to cold body, in a straight line, without affecting the intervening medium, it is referred to as heat transfer by

Accepted Answer

Radiation

Answer

Conduction

Answer

Convection

Answer

Conduction and convection

Question 3

Thermal conductivity of non-metallic amorphous solids with decrease in temperature

Accepted Answer

Decreases

Answer

Increases

Answer

Remains constant

Answer

May increase or decrease depending on temperature

Question 4

Depending on the radiating properties, a white body will be white when

Accepted Answer

ρ = 1, τ = 0 and α = 0

Answer

ρ = 0, τ = 0 and α = 1

Answer

ρ = 0, τ = 1 and α = 0

Answer

τ = 0, α+ρ = 1

Question 5

The wave length of the radiation emitted

Accepted Answer

Both (A) and (C) above

Answer

Depends on temperature only

Answer

Depends on material of body

Answer

Does not depend on material of body

Question 6

Thermal conductivity of air with rise in temperature

Accepted Answer

Increases

Answer

Decreases

Answer

Remains constant

Answer

May increase or decrease depending on temperature

Question 7

Thermal radiation extends over the range of

Accepted Answer

0.1 to 100 μ

Answer

0.01 to 0.1 μ

Answer

100 to 250 μ

Answer

250 to 1000 μ

Question 8

When heat is transferred from one particle of hot body to another by actual motion of the heated particles, it is referred to as heat transfer by

Accepted Answer

Conduction

Answer

Convection

Answer

Radiation

Answer

Convection and radiation

Question 9

In free convection heat transfer, Nusselt number is function of

Accepted Answer

Grashof number and Prandtl number

Answer

Grashof number and Reynold number

Answer

Prandtl number and Reynold number

Answer

Grashof number, Prandtl number and Reynold number