HEAT AND MASS TRANSFER QUIZ

black bodies

all coloured bodies

polished bodies

All of these

One fluid is in hottest state and other in coldest state at inlet

Both the fluids at exit are in their hottest state

Both the fluids at inlet are in their hottest state

Both the fluids at inlet (of heat exchanger where hot fluid enters) are in their coldest state

Determined by the time taken to reach 100°C from 0°C

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

Dependent on the viscosity

Less than those for liquids

More than those for solids

More than those for liquids

Film coefficient × Inside diameter Thermal conductivity

Thermal conductivity Molecular diffusivity of momentum Thermal diffusivity

Thermal conductivity Equivalent thickness of film Specific heat × Viscosity

Equivalent thickness of film

P = 0, x = 0 and a = 1

X = 0, a + p = 1

P=1, x = 0 and a = 0

P = 0, x = 1 and a = 0

Change liquid into vapour

Change vapour into liquid

Increase the temperature of a liquid or vapour

Convert water into steam and superheat it

α = 1, ρ = 0 and τ = 0

α + ρ = 1 and τ = 0

α = 0, ρ = 0 and τ = 1

α = 0, ρ = 1 and τ = 0

Steel

Brass

Copper

Aluminium

270

3

9

81