Its temperature
Nature of the body
Kind and extent of its surface
All of the above
D. All of the above
One dimensional cases only
Two dimensional cases only
Three dimensional cases only
Regular surfaces having non-uniform temperature gradients
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
Is black in colour
Reflects all heat
Transmits all heat radiations
Absorbs heat radiations of all wave lengths falling on it
Increase
Decrease
Remain unaffected
May increase/decrease depending on temperature and thickness of insulation
Blast furnace
Heating of building
Cooling of parts in furnace
Heat received by a person from fireplace
Conduction
Convection
Radiation
Scattering
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
Equal to one
Greater than one
Less than one
Equal to Nusselt number
Its temperature
Nature of the body
Kind and extent of its surface
All of the above
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.
Function of temperature
Physical property of a substance
Dimensionless parameter
All of these
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
Change vapour into liquid
Change liquid into vapour
Increase the temperature of a liquid or vapour
Convert water into steam and superheat it
Zeroth law of thermodynamics
First law of thermodynamics
Second law of thermodynamics
Kirchhoff's law
J/m² sec
J/m °K sec
W/m °K
Option (B) and (C) above
Nature of body
Temperature of body
Type of surface of body
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
W/m²K
W/m²
W/mK
W/m
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.
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)
Change vapour into liquid
Change liquid into vapour
Increase the temperature of a liquid of vapour
Convert water into steam and superheat it
Cold body to hot body
Hot body to cold body
Smaller body to larger body
Larger body to smaller body
Reflected
Refracted
Transmitted
Absorbed
Parallel flow type
Counter flow type
Cross flow type
Regenerator type
Higher
Lower
Same
Depends upon the shape of body
h = k/ ρS
h = ρS/k
h = S/ρk
h = kρ/S
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
Reynold's number
Grashoff's number
Reynold's number, Grashoff's number
Prandtl number, Grashoff's number
Thermometer
Thermistor
Thermocouple
None of these
P = 0, x = 0 and a = 1
P=1, x = 0, and a = 0
P = 0, T= 1, and a = 0
X = 0, a + p = 1