Conduction

Free convection

Forced convection

Radiation

B. Free convection

Absorptive power

Emissive power

Absorptivity

Emissivity

Conduction

Convection

Radiation

Conduction and convection

Velocity reduction method

Equal friction method

Static regains method

Dual or double method

Parallel flow type

Counter flow type

Cross flow type

Regenerator type

6

9

27

81

Stanton number

Nusselt number

Biot number

Peclet number

Stanton number

Biot number

Peclet number

Grashoff number

Added insulation will increase heat loss

Added insulation will decrease heat loss

Convective heat loss will be less than conductive heat loss

Heat flux will decrease

Radiant heat is proportional to fourth power of absolute temperature

Emissive power depends on temperature

Emissive power and absorptivity are constant for all bodies

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

k. A. (dT/dx)

k. A. (dx/dT)

k. (dT/dx)

k. (dx/dT)

Is black in colour

Reflects all heat

Transmits all heat radiations

Absorbs heat radiations of all wave lengths falling on it

First law of thermodynamics

Newton's law of cooling

Newton's law of heating

Stefan's law

Thermal resistance

Thermal coefficient

Temperature gradient

Thermal conductivity

Kirchoffs law

Stefan's law

Wien' law

Planck's law

Watt/cm² °K

Watt/cm4 °K

Watt²/cm °K⁴

Watt/cm² °K⁴

Conduction

Convection

Radiation

None of these

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

0.1

0.3

0.7

1.7

Wien's law

Planck's law

Stefan's law

Fourier's law

Higher

Lower

Same

Depends on the area of heat exchanger

Conduction

Convection

Radiation

Conduction and radiation combined

Thermal coefficient

Thermal resistance

Thermal conductivity

None of these

Higher

Lower

Same

Depends upon the shape of body

The heat transfer in liquid and gases takes place according to convection.

The amount of heat flow through a body is dependent upon the material of the body.

The thermal conductivity of solid metals increases with rise in temperature

Logarithmic mean temperature difference is not equal to the arithmetic mean temperature difference.

kcal/m²

kcal/hr °C

kcal/m² hr °C

kcal/m hr °C

Nature of the body

Temperature of the body

Type of surface of the body

All of these

Aluminium

Steel

Brass

Copper

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)

α = 1, ρ = 0 and τ = 0

α = 0, ρ = 1 and τ = 0

α = 0, ρ = 0 and τ = 1

α + ρ = 1 and τ = 0

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