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)

D. Both (A) and (B)

Zeroth law of thermodynamics

First law of thermodynamic

Second law of the thermodynamics

Kirchoff's law

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

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

One dimensional cases only

Two dimensional cases only

Three dimensional cases only

Regular surfaces having non-uniform temperature gradients

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

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

0.45

0.55

0.40

0.75

Conduction

Free convection

Forced convection

Radiation

k/h₀

2k/h₀

h₀/k

h₀/2k

One

Two

Three

Four

Grashoff number

Biot number

Stanton number

Prandtl number

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

Quantity of heat flowing in one second through one cm cube of material when opposite faces ^re maintained at a temperature difference of 1°C

Quantity of heat flowing in one second through a slab of the material of area one cm square, thickness 1 cm when its faces differ in temperature by 1°C

Heat conducted in unit time across unit area through unit thickness when a temperature difference of unity is maintained between opposite faces

All of the above

First law of thermodynamics

Newton's law of cooling

Newton's law of heating

Stefan's law

The better insulation must be put inside

The better insulation must be put outside

One could place either insulation on either side

One should take into account the steam temperature before deciding as to which insulation is put where

Their atoms collide frequently

Their atoms are relatively far apart

They contain free electrons

They have high density

Directly proportional to the thermal conductivity

Inversely proportional to density of substance

Inversely proportional to specific heat

All of the above

Nature of the body

Temperature of the body

Type of surface of the body

All of these

Change vapour into liquid

Change liquid into vapour

Increase the temperature of a liquid or vapour

Convert water into steam and superheat it

Same

Less

Greater

None of these

Nature of body

Temperature of body

Type of surface of body

All of the above

Hr (time)

Sq. m (area)

°C (temperature)

K.cal (heat)

A dimensionless parameter

Function of temperature

Used as mathematical model

A physical property of the material

m²/hr

m²/hr °C

kcal/m² hr

kcal/m. hr °C

0.1

0.23

0.42

0.51

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

Parallel flow

Counter flow

Cross flow

All 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)

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.