Heat Transfer (3151909) MCQ

MCQs of Convection

MCQ No - 1

The primary driving force for natural convection is

(A)

Shear stress forces

(B)

Buoyancy forces

(C)

Surface tension forces

(D)

None of them


B
MCQ No - 2

For the fluid flowing over a flat plate with Prandtl number greater than unity, the thermal boundary layer for laminar forced convection

(A)

is thinner than the hydrodynamic boundary layer

(B)

has thickness equal to zero

(C)

is of same thickness as hydrodynamics boundary layer 

(D)

is thicker than the hydrodynamic boundary layer 


A
MCQ No - 3

For flow of fluid over a heated plate, the following fluid properties are known: Viscosity=0.001 Pa/s, Sp. Heat at constant pressure=1 kJ/kgK, Thermal Conductivity=1W/mK; The hydrodynamic boundary layer thickness at a specified location on the plate is 1mm, thermal boundary layer thickness at the same location is 

(A)

0.001mm

(B)

0.01mm

(C)

1mm

(D)

1000mm


C
MCQ No - 4

For laminar forced convection over a flat plate, if the free stream velocity increases by a factor of 2, the average heat transfer coefficient 

(A)

remains same

(B)

decreased by a factor of 20.5

(C)

rises by a factor of 20.5

(D)

rises by a factor of 4


C
MCQ No - 5

Nusselt number is given by

(A)

hl/k

(B)

2hl/k

(C)

3hl/k

(D)

4hl/k


A