Formation of frost on evaporator in refrigerator ________________?
(A) results in loss of heat due to poor heat transfer
(B) increases heat transfer rate
(C) is immaterial
(D) can be avoided by proper design
(D) decreases compressor power
At lower temperatures and pressures, the latent heat of vaporisation of a refrigerant_________________?
(A) decreases
(B) increases
(C) remains same
(D) depends on other factors
(D) none of the above
Which of the following is not a desirable property of a refrigerant_________________?
(A) high triiscibility with oil
(B) low boiling point
(C) good electrical conductor
(D) large latent heat
(D) non-inflammable
Pick up the correct statement about giving up of heat from one medium to other in ammonia absorption system ?
(A) strong solution to weak solution
(B) weak solution to strong solution
(C) strong solution to ammonia vapour
(D) ammonia vapour to weak solution
(D) ammonia vapour to strong solution
If the evaporator temperature of a plant is lowered, keeping the condenser temperature constant, the h.p. of compressor required will be________________?
(A) same
(B) more
(C) less
(D) more/less depending on rating
(D) unpredictable
Highest pressure encountered in a refrigeration system should be________________?
(A) critical pressure of refrigerant
(B) much below critical pressure
(C) much above critical pressure
(D) near critical pressure
(D) there is no such restriction
A certain refrigerating system has a normal operating suction pressure of 10 kg/cm gauge and condensing pressure of about 67 kg/cm. The refrigerant used is________________?
(A) Ammonia
(B) Carbon dioxide
(C) Freon
(D) Brine
(D) Hydrocarbon refrigerant
Where does the lowest temperature occur in a vapour compression cycle ?
(A) condenser
(B) evaporator
(C) compressor
(D) expansion valve
(D) receiver
True stress-strain curve for materials is plotted between__________________?
(A) load/original cross-sectional area and change in length/original length
(B) load/instantaneous cross-sectional area original area and log
(C) load/instantaneous cross-sectional area and change in length/original length
(D) load/instantaneous area and instantaneous area/original area
(D) none of the above
Percentage reduction of area in performing tensile test on cast iron may be of the order of__________________?
(A) 50%
(B) 25%
(C) 0%
(D) 15%
(D) 60%.