irregular surfaces
non-uniform temperature surfaces
one dimensional cases only
two dimensional cases
✅ The correct answer is option C.
Heat Transfer
An infinite parallel planes with emissivities e1 and e2, the interchange factor for radiation from surface 1 to surface 2 is given by
e1 + e2
e1e2
✅ The correct answer is option A.
The temperature of air recorded by a thermometer, when it is not effected by the moisture present in the air, is called
wet bulb temperature
dry bulb temperature
dew point temperature
none of these
✅ The correct answer is option B.
Conduction is a process of heat transfer
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
✅ The correct answer is option A.
In which of the following refrigeration system, waste heat can be effectively used?
Vapour compression cycle
Vapour absorption cycle
Air refrigeration cycle
none of these
✅ The correct answer is option B.
The sulphur sticks, in case of leakage of ammonia refrigerant, gives white smoke.
TRUE
FALSE
✅ The correct answer is option A.
The coefficient of performance (C.O.P.) of a refrigerator working as a heat pump is given by
(C.O.P.)P = (C.O.P.)R + 2
(C.O.P.)P = (C.O.P.)R + 1
(C.O.P)P = (C.O.P)R – 1
(C.O.P)P = (C.O.P)R
✅ The correct answer is option B.
It is desired to condition the outside air from 70% relative humidity and 45° C dry bulb temperature to 50% relative humidity and 25° C dry bulb temperature (room condition). The practical arrangement will be
dehumidification
cooling and humidification
cooling and dehumidification
dehumidification and p
✅ The correct answer is option C.
When α is absorptivity, ρ is reflectivity and τ is transmittivity, then for a diathermanous body,
α = 1, ρ = 0 and τ = 0
α = 0, ρ = 1 and τ = 0
α = 0, ρ = 0 and τ = 1
α + ρ = 1 and τ = 0
✅ The correct answer is option D.