HEAT AND MASS TRANSFER QUIZ

Fouling factor is used

When a liquid exchanges heat with a gas

In case of Newtonian fluids

In heat exchanger design as a safety factor

None of these

TRUE ANSWER : ?
YOUR ANSWER : ?

The heat transfer takes place according to

Kirchhoff's law

Second law of thermodynamics

First law of thermodynamics

Zeroth law of thermodynamics

TRUE ANSWER : ?
YOUR ANSWER : ?

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

Convection

Radiation

Conduction

Conduction and convection

TRUE ANSWER : ?
YOUR ANSWER : ?

The automobile radiator is a heat exchanger of

Counter flow type

Regenerator type

Parallel flow type

Cross flow type

TRUE ANSWER : ?
YOUR ANSWER : ?

Two balls of same material and finish have their diameters in the ratio of 2: 1 and both are heated to same temperature and allowed to cool by radiation. Rate of cooling by big ball as compared to smaller one will be in the ratio of

0.043055555555556

0.16736111111111

0.084027777777778

0.042361111111111

TRUE ANSWER : ?
YOUR ANSWER : ?

A composite slab has two layers of different materials with thermal conductivities k₁ and k₂. If each layer has the same thickness, then the equivalent thermal conductivity of the slab will be

(k₁ + k₂)

2 k₁ k₂/ (k₁ + k₂)

k₁ k₂

(k₁ + k₂)/ k₁ k₂

TRUE ANSWER : ?
YOUR ANSWER : ?

The expression Q = ρ AT4 is called

Newton Reichmann equation

Stefan-Boltzmann equation

Joseph-Stefan equation

Fourier equation

TRUE ANSWER : ?
YOUR ANSWER : ?

Thermal conductivity of water in general with rise in temperature

Decreases

May increase or decrease depending on temperature

Increases

Remain constant

TRUE ANSWER : ?
YOUR ANSWER : ?

According of Kirchhoff's law

Ratio of emissive power to absorptive power for all bodies is same and is equal to the emissive power of a perfectly black body

Radiant heat is proportional to fourth power of absolute temperature

Emissive power depends on temperature

Emissive power and absorptivity are constant for all bodies

TRUE ANSWER : ?
YOUR ANSWER : ?

All radiations in a black body are

Refracted

Reflected

Absorbed

Transmitted

TRUE ANSWER : ?
YOUR ANSWER : ?