I.C. engine

Air preheaters

Heating of building in winter

None of the above

D. None of the above

Wien's law

Planck's law

Stefan's law

Fourier's law

Absolute temperature

Square of the absolute temperature

Cube of the absolute temperature

Fourth power of the absolute temperature

Conduction

Convection

Radiation

None of these

Radiators in automobile

Condensers and boilers in steam plants

Condensers and evaporators in refrigeration and air conditioning units

All of the above

Directly proportional to the thermal conductivity

Inversely proportional to density of substance

Inversely proportional to specific heat

All of the above

Thermometer

Thermistor

Thermocouple

None of these

A grey body is one which absorbs all radiations incident on it.

At thermal equilibrium, the emissivity and absorptivity are same.

The energy absorbed by a body to the total energy falling on it, is called emissivity.

A perfect body is one which is black in colour.

Irregular surfaces

Nonuniform temperature surfaces

One dimensional cases only

Two dimensional cases only

Parallel flow

Counter flow

Cross flow

All of these

Equal to one

Greater than one

Less than one

Equal to Nusselt number

Varies with temperature

Varies with wavelength of the incident ray

Is equal to its emissivity

Does not vary with temperature and. wavelength of the incident ray

P = 0, x = 0 and a = 1

P=1, x = 0 and a = 0

P = 0, x = 1 and a = 0

X = 0, a + p = 1 Where a = absorptivity, p = reflectivity, X = transmissivity.

Composition

Density

Porosity

All of the above

Is black in colour

Reflects all heat

Transmits all heat radiations

Absorbs heat radiations of all wave lengths falling on it

Conduction

Convection

Radiation

Conduction and convection

Its temperature

Nature of the body

Kind and extent of its surface

All of the above

Increases

Decreases

Remain constant

May increase or decrease depending on temperature

Shorter wavelength

Longer wavelength

Remain same at all wavelengths

Wavelength has nothing to do with it

Nature of the body

Temperature of the body

Type of surface of the body

All of these

Conduction

Convection

Radiation

Scattering

k/h₀

2k/h₀

h₀/k

h₀/2k

Pb = pa - pv

Pb = pa + pv

Pb = pa × pv

Pb = pa/pv

Nature of body

Temperature of body

Type of surface of body

All 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

Varies with temperature

Varies with the wave length of incident ray

Varies with both

Does not vary with temperature and wave length of the incident ray

Free electrons

Atoms colliding frequency

Low density

Porous body

2 TR

4 TR

8 TR

10 TR

Thermal conductivity to the equivalent thickness of the film of fluid

Temperature drop through the films of fluids to the thickness of film of fluids

Thickness of film of fluid to the thermal conductivity

Thickness of film of fluid to the temperature drop through the films of fluids

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

K cal/kg m² °C

K cal m/hr m² °C

K cal/hr m² °C

K calm/hr °C