Black radiation

Full radiation

Total radiation

All of these

D. All of these

Aluminium

Steel

Brass

Copper

Face area

Time

Thickness

Temperature difference

At all temperatures

At one particular temperature

When system is under thermal equilibrium

At critical temperature

Minimum energy

Maximum energy

Both (A) and (B)

None of these

S.H/(S.H + L.H)

(S.H + L.H) /S.H

(L.H - S.H)/S.H

S.H/(L.H - S.H)

Improve heat transfer

Provide support for tubes

Prevent stagnation of shell side fluid

All of these

Both the fluids at inlet (of heat exchanger where hot fluid enters) are in their coldest state

Both the fluids at inlet are in their hottest state

Both the fluids at exit are in their hottest state

One fluid is in hottest state and other in coldest state at inlet

Domestic refrigerators

Water coolers

Room air conditioners

All of these

Their atoms collide frequently

Their atoms are relatively far apart

They contain free electrons

They have high density

Reflected

Refracted

Transmitted

Absorbed

Energy transferred by convection to that by conduction

Kinematic viscosity to thermal diffusivity

Inertia force to viscous force

None of the above

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

kcal/m²

kcal/hr °C

kcal/m² hr °C

kcal/m hr °C

The total radiation from a black body per second per unit area is directly proportional to the fourth power of the absolute temperature

The wave length corresponding to the maximum energy is proportional to the absolute temperature

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

None of the above

RN = hl/k

RN = μ cp/k

RN = ρ V l /μ

RN = V²/t.cp

One dimensional cases only

Two dimensional cases only

Three dimensional cases only

Regular surfaces having non-uniform temperature gradients

Absolute temperature

T²

T⁵

T

Less than those for gases

Less than those for liquids

More than those for liquids and gases

More or less same as for liquids and gases

_{min}/U

_{min}

_{min}

_{min}

Conduction

Convection

Radiation

None of these

Conduction

Free convection

Forced convection

Radiation

Watt/mK

Watt/m²K²

^{4}

Watt/mK²

Kirchoffs law

Stefan's law

Wien' law

Planck's law

Liquids

Energy

Temperature

Entropy

Equal to one

Greater than one

Less than one

Equal to Nusselt number

Melting of ice

Boiler furnaces

Condensation of steam in condenser

None of these

Conduction

Convection

Radiation

Conduction and convection

Irregular surfaces

Nonuniform temperature surfaces

One dimensional cases only

Two dimensional cases only

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.

K cal/kg m² °C

K cal m/hr m² °C

K cal/hr m² °C

K calm/hr °C