Remain same
Decreases
Increases
May increase or decrease depending upon temperature
D. May increase or decrease depending upon temperature
Equal to
Directly proportional to
Inversely proportional to
None of these
Convection
Radiation
Conduction
Both convection and conduction
Conduction
Convection
Radiation
Conduction and convection
0.002
0.02
0.01
0.1
Irregular surfaces
Nonuniform temperature surfaces
One dimensional cases only
Two dimensional cases only
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
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
Absolute temperature
T²
T⁵
T
Emissivity
Transmissivity
Reflectivity
Intensity of radiation
6
9
27
81
Conduction
Convection
Radiation
None of these
Absorptive power
Emissive power
Absorptivity
Emissivity
kcal/m²
kcal/hr °C
kcal/m² hr °C
kcal/m hr °C
J/m² sec
J/m °K sec
W/m °K
Option (B) and (C) above
Composition
Density
Porosity
All of the above
Conduction
Convection
Radiation
Conduction and convection
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
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
Conduction
Free convection
Forced convection
Radiation
Zeroth law of thermodynamics
First law of thermodynamics
Second law of thermodynamics
Kirchhoff's law
I.C. engine
Air preheaters
Heating of building in winter
None of the above
Blast furnace
Heating of building
Cooling of parts in furnace
Heat received by a person from fireplace
In heat exchanger design as a safety factor
In case of Newtonian fluids
When a liquid exchanges heat with a gas
None of the above
Electric heater
Steam condenser
Boiler
Refrigerator condenser coils
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
Stanton number
Biot number
Peclet number
Grashoff number
Glass
Water
Plastic
Air
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 = 1 Where a = absorptivity, p = reflectivity, x = transmissivity
In conduction, reduction in the thickness of the material and an increase in thermal conductivity.
In convection, stirring of the fluid and cleaning the heating surface.
In radiation, increasing the temperature and reducing the emissivity.
All of the above
Thermal resistance
Thermal coefficient
Temperature gradient
Thermal conductivity