HEAT AND MASS TRANSFER QUIZ

The ratio of Nusselt number and the product of Reynold's number and Prandtl number is equal to

Biot number

Stanton number

Peclet number

Grashoff number

TRUE ANSWER : ?
YOUR ANSWER : ?

Thermal diffusivity is

Used as mathematical model

A dimensionless parameter

Function of temperature

A physical property of the material

TRUE ANSWER : ?
YOUR ANSWER : ?

Depending on the radiating properties, a body will be white when(Where a = absorptivity, p = reflectivity, x = transmissivity)

X = 0, a + p = 1

P = 0, x = 0 and a = 1

P = 0, x = 1 and a = 0

P=1, T = 0 and a = 0

TRUE ANSWER : ?
YOUR ANSWER : ?

The emissive power of a body depends upon its

Physical nature

Temperature

Wave length

All of these

TRUE ANSWER : ?
YOUR ANSWER : ?

Which of the following is a case of steady state heat transfer?

Air preheaters

Heating of building in winter

I.C. engine

None of these

TRUE ANSWER : ?
YOUR ANSWER : ?

A perfect black body is one which

Reflects all heat

Is black in colour

Absorbs heat radiations of all wave lengths falling on it

Transmits all heat radiations

TRUE ANSWER : ?
YOUR ANSWER : ?

Wien’s law states that the wave length corresponding to ________ is proportional to the absolute temperature.

Minimum energy

None of these

Maximum energy

Both (A) and (B)

TRUE ANSWER : ?
YOUR ANSWER : ?

The critical thickness of insulation for a sphere is

2k/h₀

h₀/k

k/h₀

h₀/2k

TRUE ANSWER : ?
YOUR ANSWER : ?

The total emissivity power is .defined as the total amount of radiation emitted by a black body per unit

Temperature

Thickness

Time

Area

TRUE ANSWER : ?
YOUR ANSWER : ?

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

May increase or decrease depending on temperature

Remain constant

Decreases

Increases

TRUE ANSWER : ?
YOUR ANSWER : ?

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