HEAT AND MASS TRANSFER QUIZ

Thermal conductivity of wood depends on

Temperature

Density

All of these

Moisture

TRUE ANSWER : ?
YOUR ANSWER : ?

The thickness of thermal and hydrodynamic boundary layer is equal if Prandtl number is

Equal to Nusselt number

Greater than one

Equal to one

Less than one

TRUE ANSWER : ?
YOUR ANSWER : ?

The unit of Stefan Boltzmann constant is

watt/cm4 °K

watt/cm3 °K

watt/cm2 °K⁴

watt2/cm °K⁴

TRUE ANSWER : ?
YOUR ANSWER : ?

Unit of thermal conductivity in S.I. units is

W/m °K

Option (B) and (C) above

J/m °K sec

J/m² sec

TRUE ANSWER : ?
YOUR ANSWER : ?

In a shell and tube heat exchanger, baffles are provided on the shell side to

Improve heat transfer

Prevent stagnation of shell side fluid

Provide support for tubes

All of these

TRUE ANSWER : ?
YOUR ANSWER : ?

Conduction is a process of heat transfer

None of these

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

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

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

TRUE ANSWER : ?
YOUR ANSWER : ?

The ratio of the thickness of thermal boundary layer to the thickness of hydrodynamic boundary layer is equal to (Prandtl number) n, where n is equal to

=-2/3

-1

1

=-1/3

TRUE ANSWER : ?
YOUR ANSWER : ?

The ratio of surface convection resistance to the internal conduction resistance is known as

Biot number

Prandtl number

Grashoff number

Stanton number

TRUE ANSWER : ?
YOUR ANSWER : ?

Depending on the radiating properties, a body will be black when(Where a = absorptivity, p = reflectivity, X = transmissivity.)

X = 0, a + p = 0

P= 1, T = 0 and a = 0

P = 0, x = 1 and a = 0

P = 0, x = 0 and a = 1

TRUE ANSWER : ?
YOUR ANSWER : ?

Unit of thermal conductivity in M.K.S. units is

K cal/kg m² °C

K calm/hr °C

K cal/hr m² °C

K cal m/hr m² °C

TRUE ANSWER : ?
YOUR ANSWER : ?