Thermal coefficient
Thermal resistance
Thermal conductivity
None of these
B. Thermal resistance
Conduction
Convection
Radiation
None of these
-1/3
-2/3
1
-1
Face area
Time
Thickness
Temperature difference
Stanton number
Biot number
Peclet number
Grashoff number
The total radiation from a black body per second per unit area is directly proportional to the fourth power of the absolute temperature
The wave length corresponding to the maximum energy is proportional to the absolute temperature
The ratio of the emissive power and absorptive power of all bodies is the same and is equal to the emissive power of a perfectly black body
None of the above
Aluminium
Steel
Brass
Copper
P = 0, x = 0 and a = 1
P= 1, T = 0 and a = 0
P = 0, x = 1 and a = 0
X = 0, a + p = 0 Where a = absorptivity, p = reflectivity, X = transmissivity.
Directly proportional to the thermal conductivity
Inversely proportional to density of substance
Inversely proportional to specific heat
All of the above
Kirchhoff's law
Stefan's law
Wines law
Planck's law
Glass
Water
Plastic
Air
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
Increases
Decreases
Remain constant
May increase or decrease depending on temperature
2 TR
4 TR
8 TR
10 TR
Convection
Radiation
Forced convection
Free convection
Change vapour into liquid
Change liquid into vapour
Increase the temperature of a liquid of vapour
Convert water into steam and superheat it
0
0.5
0.75
1
Function of temperature
Physical property of a substance
Dimensionless parameter
All of these
Cold body to hot body
Hot body to cold body
Smaller body to larger body
Larger body to smaller body
Energy transferred by convection to that by conduction
Kinematic viscosity to thermal diffusivity
Inertia force to viscous force
None of the above
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
0.45
0.55
0.40
0.75
High thickness of insulation
High vapour pressure
Less thermal conductivity insulator
A vapour seal
h = k/ ρS
h = ρS/k
h = S/ρk
h = kρ/S
Thermal conductivity
Thermal diffusivity
Density
Dynamic viscosity
Iron
Lead
Concrete
Wood
RN = hl/k
RN = μ cp/k
RN = ρ V l /μ
RN = V²/t.cp
Convection
Radiation
Conduction
Both convection and conduction
Change vapour into liquid
Change liquid into vapour
Increase the temperature of a liquid or vapour
Convert water into steam and superheat it
Grey body
Brilliant white polished body
Red hot body
Black body
Conduction
Convection
Radiation
Conduction and convection