GATE Heat & Mass Transfer Objective Questions

Heat and Mass Transfer : Objective Questions

1. The fraction of radiative energy leaving one surface that strikes the other surface is called?

A. Radiative flux

B. View factor

C. Reradiation flux

D. Emissive power of the first surface

View Answer/Explanation

Correct Answer is C

2. Prandtl number of a flowing fluid greater than unity indicates that hydrodynamic boundary layer thickness is –

A. greater than the thermal boundary layer thickness

B. equal to the thermal boundary layer thickness

C. greater than the hydrodynamic boundary layer thickness

D. independent of thermal boundary layer thickness

View Answer/Explanation

Correct Answer is A

3. Which one of the following number represents the ratio of kinematic viscosity to the thermal diffusivity?

A. Mach Number

B. Nusselt Number

C. Prandtl Number

D. Grashoff Number

View Answer/Explanation

Correct Answer is C

4. Which one of the following non-dimensional numbers are used for transition from laminar to turbulent flow in free convection?

A. Reynolds Number

B. Peclet Number

C. Rayleigh Number

D. Grashoff Number

View Answer/Explanation

Correct Answer is D

5. Heat transfer takes place according to

A. Zeroth law of thermodynamics

B. 1st Law of thermodynamics

C. 2nd Law of thermodynamics

D. 3rd Law of thermodynamics

View Answer/Explanation

Correct Answer is C

2nd Law Statement – Heat flow one reservoir (High temp.) to another at low temperature.

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