HEAT AND MASS TRANSFER QUIZ

None of these

Emissive power

Emissivity

Absorptive power

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

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

All of these

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

Reflects all heat

Is black in colour

Transmits all heat radiations

Absorbs heat radiations of all wave lengths falling on it

2k/h₀

k/h₀

h₀/2k

h₀/k

Convective heat loss will be less than conductive heat loss

Heat flux will decrease

Added insulation will increase heat loss

Added insulation will decrease heat loss

Radiation

Conduction

Convection

Both convection and conduction

Option (B) and (C) above

W/m °K

J/m² sec

J/m °K sec

Emissive power depends on temperature

Radiant heat is proportional to fourth power of absolute temperature

Ratio of emissive power to absorptive power for all bodies is same and is equal to the emissive power of a perfectly black body

Emissive power and absorptivity are constant for all bodies

Energy

Temperature

Entropy

Liquids

Thickness of film of fluid to the thermal conductivity

Thickness of film of fluid to the temperature drop through the films of fluids

Thermal conductivity to the equivalent thickness of the film of fluid

Temperature drop through the films of fluids to the thickness of film of fluids