Thermometer

Thermistor

Thermocouple

None of these

C. Thermocouple

_{m} = (Δt_{1} - Δt_{2})/ log_{e} (Δt_{1}/Δt_{2})

_{m} = log_{e} (Δt_{1}/Δt_{2})/ (Δt_{1} - Δt_{2})

_{m} = t_{m} = (Δt_{1} - Δt_{2}) log_{e} (Δt_{1}/Δt_{2})

_{m} = log_{e} (Δt_{1} - Δt_{2})/ Δt_{1}/Δt_{2}

Kirchhoff's law

Stefan's law

Wines law

Planck's law

h = k/ ρS

h = ρS/k

h = S/ρk

h = kρ/S

The time taken to attain the final temperature to be measured

The time taken to attain 50% of the value of initial temperature difference

The time taken to attain 63.2% of the value of initial temperature difference

Determined by the time taken to reach 100°C from 0°C

Same

More

Less

Depends on other factors

Its temperature

Nature of the body

Kind and extent of its surface

All of the above

I.C. engine

Air preheaters

Heating of building in winter

None of the above

Hr (time)

Sq. m (area)

°C (temperature)

K.cal (heat)

Conduction

Convection

Radiation

Scattering

Moisture

Density

Temperature

All of the above

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

Conduction

Convection

Radiation

Conduction and convection

_{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})

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

20°C

40°C

60°C

66.7°C

Thermal resistance

Thermal coefficient

Temperature gradient

Thermal conductivity

Conduction

Convection

Radiation

Conduction and convection

Thermometer

Thermistor

Thermocouple

None of these

Density

Coefficient of viscosity

Gravitational force

All 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.

RN = hl/k

RN = μ cp/k

RN = ρ V l /μ

RN = V²/t.cp

Direct mixing of hot and cold fluids

A complete separation between hot and cold fluids

Flow of hot and cold fluids alternately over a surface

Generation of heat again and again

k. A. (dT/dx)

k. A. (dx/dT)

k. (dT/dx)

k. (dx/dT)

1 : 1

2 : 1

1 : 2

4 : 1

25 mm

40 mm

160 mm

800 mm

Universal gas constant

Kinematic viscosity

Thermal conductivity

Planck's constant

Absorptive power

Emissive power

Emissivity

None of these

Stanton number

Biot number

Peclet number

Grashoff number

Watt/mK

Watt/m²K²

^{4}

Watt/mK²

Thermal conductivity

Thermal diffusivity

Density

Dynamic viscosity