From one particle of the body to another without the actual motion of the particles
From one particle of the body to another by the actual motion of the heated particles
From a hot body to a cold body, in a straight line, without affecting the intervening medium
None of the above
A. From one particle of the body to another without the actual motion of the particles
Hr (time)
Sq. m (area)
°C (temperature)
K.cal (heat)
I.C. engine
Air preheaters
Heating of building in winter
None 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.
Watt/mK
Watt/m²K²
Watt/m²K4
Watt/mK²
High thickness of insulation
High vapour pressure
Less thermal conductivity insulator
A vapour seal
Conduction
Convection
Radiation
Conduction and convection
Grashoff number
Biot number
Stanton number
Prandtl number
Reynold's number
Grashoff's number
Reynold's number, Grashoff's number
Prandtl number, Grashoff's number
Parallel flow type
Counter flow type
Cross flow type
Regenerator type
Grey body
Brilliant white polished body
Red hot body
Black body
Increases
Decreases
Remain constant
May increase or decrease depending on temperature
Maximum
Minimum
Zero
None of these
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
Conduction
Free convection
Forced convection
Radiation
Radiators in automobile
Condensers and boilers in steam plants
Condensers and evaporators in refrigeration and air conditioning units
All of the above
Absolute temperature
Square of temperature
Fourth power of absolute temperature
Fourth power of temperature
Q = 2πkr1 r2 (T1 - T2)/ (r2 - r1)
Q = 4πkr1 r2 (T1 - T2)/ (r2 - r1)
Q = 6πkr1 r2 (T1 - T2)/ (r2 - r1)
Q = 8πkr1 r2 (T1 - T2)/ (r2 - r1)
Domestic refrigerators
Water coolers
Room air conditioners
All of these
Nature of body
Temperature of body
Type of surface of body
All of the above
Grashoff number and Reynold number
Grashoff number and Prandtl number
Prandtl number and Reynold number
Grashoff number, Prandtl number and Reynold number
Conduction
Convection
Radiation
Conduction and convection
Increase
Decrease
Remain unaffected
May increase/decrease depending on temperature and thickness of insulation
Directly proportional to the surface area of the body
Directly proportional to the temperature difference on the two faces of the body
Dependent upon the material of the body
All of the above
-1/3
-2/3
1
-1
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
20°C
40°C
60°C
66.7°C
Absorptive power
Emissive power
Absorptivity
Emissivity
Thermal coefficient
Thermal resistance
Thermal conductivity
None of these
Black bodies
Polished bodies
All coloured bodies
All of the above
Reflected
Refracted
Transmitted
Absorbed