Fourier equation

Stefan-Boltzmann equation

Newton Reichmann equation

Joseph-Stefan equation

B. Stefan-Boltzmann equation

h₁ + h₂ + h₃

(h₁.h₂.h₃)1/3

1/h₁ + 1/h₂ + 1/h₃

None of these

Same

Less

Greater

None of these

Directly proportional to thermal conductivity

Inversely proportional to density of substance

Inversely proportional to specific heat

All of the above

Increases

Decreases

Remain constant

May increase or decrease depending on temperature

High thickness of insulation

High vapour pressure

Less thermal conductivity insulator

A vapour seal

Melting of ice

Boiler furnaces

Condensation of steam in condenser

None of these

Q = [2πlk (T₁ - T₂)]/2.3 log (r₂/r₁)

Q = 2.3 log (r₂/r₁)/[2πlk (T₁ - T₂)]

Q = [2π (T₁ - T₂)]/2.3 lk log (r₂/r₁)

Q = = 2πlk/2.3 (T₁ - T₂) log (r₂/r₁)

First law of thermodynamics

Newton's law of cooling

Newton's law of heating

Stefan's law

Black radiation

Full radiation

Total radiation

All of these

Stanton number

Biot number

Peclet number

Grashoff number

It is impossible to transfer heat from low temperature source to t high temperature source

Heat transfer by radiation requires no medium

All bodies above absolute zero emit radiation

Heat transfer in most of the cases takes place by combination of conduction, convection and radiation

Thermal resistance

Thermal coefficient

Temperature gradient

Thermal conductivity

Nature of body

Temperature of body

Type of surface of body

All of the above

One dimensional cases only

Two dimensional cases only

Three dimensional cases only

Regular surfaces having non-uniform temperature gradients

Increase

Decrease

Remain unaffected

May increase/decrease depending on temperature and thickness of insulation

In heat exchanger design as a safety factor

In case of Newtonian fluids

When a liquid exchanges heat with a gas

None of the above

Stanton number

Nusselt number

Biot number

Peclet number

K cal/kg m² °C

K cal m/hr m² °C

K cal/hr m² °C

K calm/hr °C

Increases

Decreases

Remain constant

May increase or decrease depending on temperature

Equivalent thickness of film

Thermal conductivity Equivalent thickness of film Specific heat × Viscosity

Thermal conductivity Molecular diffusivity of momentum Thermal diffusivity

Film coefficient × Inside diameter Thermal conductivity

Below which a gas does not obey gas laws

Above which a gas may explode

Below which a gas is always liquefied

Above which a gas will never liquefied

Glass

Water

Plastic

Air

Directly proportional to the surface area

Directly proportional to the difference of temperatures between the two bodies

Either (A) or (B)

Both (A) and (B)

Convection

Radiation

Conduction

Both convection and conduction

Change vapour into liquid

Change liquid into vapour

Increase the temperature of a liquid or vapour

Convert water into steam and superheat it

-1/3

-2/3

1

-1

One

Two

Three

Four

k/h₀

2k/h₀

h₀/k

h₀/2k

Solids

Liquids

Gases

None of these

_{1} r_{2} (T_{1} - T_{2})/ (r_{2} - r_{1})

_{1} r_{2} (T_{1} - T_{2})/ (r_{2} - r_{1})

_{1} r_{2} (T_{1} - T_{2})/ (r_{2} - r_{1})

_{1} r_{2} (T_{1} - T_{2})/ (r_{2} - r_{1})