291. In a pressure enthalpy chart, the space to the left of the saturated liquid line represents
wet vapour region
superheated vapour region
sub-cooled liquid region
none of these
✅ The correct answer is option C.
Heat Transfer, Refrigeration and Air Conditioning MCQs
292. The condition of refrigerant after passing through the expansion or throttle valve, in a vapour compression system is
high pressure saturated liquid
wet vapour
very wet vapour
dry vapour
✅ The correct answer is option C.
293. Wein’s law states that the wave length corresponding to __________ is proportional to the absolute temperature.
minimum energy
maximum energy
✅ The correct answer is option B.
294. Thermal conductivity of solid metals __________ with rise in temperature.
remains same
decreases
increases
✅ The correct answer is option B.
295. A pressure gauge on the discharge side of a refrigerant compressor reads too high. The reasons will be
lack of cooling water
water temperature being high
dirty condenser surface
all of these
✅ The correct answer is option D.
296. In a pressure enthalpy chart, the space between the saturated liquid line and saturated vapour line, represents sub-cooled liquid region.
TRUE
FALSE
✅ The correct answer is option B.
297. The logarithmic mean temperature difference ™ is given by (where Δt1 and Δt2 are temperature differences between the hot and cold fluids at entrance and exit)
tm = (Δt1 – Δt1) loge(Δt1/Δt1)
✅ The correct answer is option A.
298. Wet bulb temperature is the temperature of air recorded by a thermometer, when
it is not effected by the moisture present in the air
its bulb is surrounded by a wet cloth exposed to the air
the moisture present in it begins to condense
none of the above
✅ The correct answer is option B.
299. The curved lines on a psychrometric chart indicates
dry bulb temperature
wet bulb temperature
dew point temperature
relative humidity
✅ The correct answer is option D.
300. The boiling point of __________ is -10.5°C.
ammonia
R-12
sulphur dioxide
carbon dioxide
✅ The correct answer is option C.