The vapor pressure of refrigerant should be_________________?

lower than atmospheric pressure

higher than atmospheric pressure

The suction pipe diameter of refrigerating unit compressor in comparison to delivery side is_________________?

smaller/bigger depending on capacity

The refrigeration effect in a dry evaporator compared to flooded evaporator in a similar plant is_________________?

more or less depending on ambient conditions

The lower horizontal line of the refrigeration cycle plotted on pressure-enthalpy-diagram represents_____________________?

compression of the refrigerant vapour

condensation of the refrigerant vapour

evaporation of the refrigerant liquid

compression of the refrigerant vapour

metering of the refrigerant liquid

The leaks in a refrigeration system using Freon are detected by____________________?

sulphur sticks which on detection gives white smoke

halide torch which on detection produces greenish flame lighting

sulphur sticks which on detection gives white smoke

The general rule for rating refrigeration systems (excepting for C02 system) is to approximate following h.p. per ton of refrigeration__________________?

2 to 5 h.p. per ton of refrigeration

0.1 to 0.5 h.p. per ton of refrigeration

0.5 to 0.8 h.p. per ton of refrigeration

1 to 2 h.p. per ton of refrigeration

2 to 5 h.p. per ton of refrigeration

5 to 10 h.p. per ton refrigeration

The evolution of heat of solution takes place in ammonia absorption plant when _____________________?

ammonia vapour is driven out of solution

ammonia vapour goes into solution

ammonia vapour is driven out of solution

lithium bromide mixes with ammonia

weak solution mixes with strong solution

lithium bromide is driven out of solution

The COP of a vapor compression plant in comparison to vapor absorption plant is ________________?

more/less depending on size of plant

The C.O.P. of a refrigeration cycle with lowering of condenser temperature, keeping the evaporator temperature constant, will__________________?

may increase or decrease depending on the type of refrigerant used

The C.O.P of a refrigeration cycle with increase in evaporator temperature, keeping condenser temperature constant, will______________________?

may increase or decrease depending on the type of refrigerant used

The COP of a domestic refrigerator___________________?

depends upon the weather conditions

The condensing pressure due to the presence of non-condensable gases, as compared to that actually required for condensing temperatures without non-condensable gases ____________________ ?

may be higher or lower depending upon the nature of non-condensable gases

The coefficient of performance is the ratio of the refrigerant effect to the_________________?

enthalpy increase in compressor

The advantage of dry compression is that________________?

it permits higher speeds to be used

it permits complete evaporation in the evaporator

it results in high volumetirc and mechanical efficiency

Reducing suction pressure in refrigeration cycle_________________?

increases power required per ton of refrigeration

lowers compressor capacity because vapour is lighter

reduces weight displaced by piston

Pick up the incorrect statement?

concentration of solution coming out of lithium bromide generator is more in comparison to that entering the generator

lithium bromide used in vapour absorption cycle is nonvolatile

lithium bromide plant can’t operate below 0°C

a separator is used in lithium bromide plant to remove the unwanted water vapour by condensing

concentration of solution coming out of lithium bromide generator is more in comparison to that entering the generator

weak solution in liquid heat exchanger gives up heat to the strong solution

Pick up the correct statement about giving up of heat from one medium to other in ammonia absorption system ?

strong solution to ammonia vapour

strong solution to weak solution

weak solution to strong solution

strong solution to ammonia vapour

ammonia vapour to weak solution

ammonia vapour to strong solution

One ton of the refrigeration is_________________?

the refrigeration effect to produce 1 ton of ice at NTP conditions

the standard unit used in refrigeration problems

the cooling effect produced by melting 1 ton of ice

the refrigeration effect to freeze 1 ton of water at 0°C into ice at 0°C in 24 hours

the refrigeration effect to produce 1 ton of ice at NTP conditions

the refrigeration effect to produce 1 ton of ice in 1 hour time

One of the purposes of sub-cooling the liquid refrigerant is to________________?

reduce compressor discharge temperature

ensure that only liquid and not the vapour enters the expansion (throttling) valve

On the pressure-enthalpy diagram, condensation and desuperheating is represented by a horizontal line because the process ________________?

takes place at constant temperature

takes place at constant entropy

takes place at constant enthalpy

takes place at constant pressure

Moisture in freon refrigeration system causes________________?

freezing automatic regulating valve

In vapour compression cycle, the conditii of refrigerant is saturated liquid________________?

before passing through the condensei

after passing through the condenser

before passing through the condensei

after passing through the expansion throttle valve

before entering the expansion valve

In vapour compression cycle using NH3 as refrigerant, initial charge is filled at_________________?

low pressure side near receiver

high pressure side close to receiver

low pressure side near receiver

In vapour compression cycle the condition of refrigerant is superheated vapour _____________________?

after passing through the expansion or throttle valve

after passing through the condenser

before passing through the condenser

after passing through the expansion or throttle valve

before [entering the expansion valve

In vapor compression cycle the condition off refrigerant is dry saturated vapor________________?

after passing through the condenser

before passing through the condenser

after passing through the expansion or throttle valve

before entering the expansion valve

89 + Mcqs in Refrigeration in Mechanical Engineering Questions Page 1 McqOptions

1.	Which of the following refrigerants has lowest freezing point_______________?
A.	Freon-12
B.	NH3
C.	C02
D.	Freon-22
E.	S02
Answer» E. S02

Discussion

2.	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
E.	non-inflammable
Answer» D. large latent heat

Discussion

3.	Which of the following cycles uses air as the refrigerant__________________?
A.	Ericsson
B.	Stirling
C.	Carnot
D.	Bell-coleman
E.	none of the above
Answer» E. none of the above

Discussion

4.	Where does the lowest temperature occur in a vapour compression cycle ?
A.	condenser
B.	evaporator
C.	compressor
D.	expansion valve
E.	receiver
Answer» C. compressor

Discussion

5.	Vertical lines on pressure-enthalpy chart show constant_______________?
A.	pressure lines
B.	temperature lines
C.	total heat lines
D.	entropy lines
E.	volume lines
Answer» D. entropy lines

Discussion

6.	Vapor compression refrigeration is some what like ____________________?
A.	Carnot cycle
B.	Rankine cycle
C.	reversed Camot cycle
D.	reversed Rankine cycle
E.	none of the above
Answer» F.

Discussion

7.	Under-cooling in a refrigeration cycle_________________?
A.	increases COP
B.	decreases COF
C.	COP remains unaltered
D.	other factors decide COP
E.	unperdictable
Answer» B. decreases COF

Discussion

8.	The vapor pressure of refrigerant should be_________________?
A.	lower than atmospheric pressure
B.	higher than atmospheric pressure
C.	equal to atmospheric pressure
D.	could be anything
E.	none of the above
Answer» C. equal to atmospheric pressure

Discussion

9.	The vapor compression refrigerator employs the following cycle_________________?
A.	Rankine
B.	Carnot
C.	Reversed Rankine
D.	Brayton
E.	Reversed Carnot
Answer» F.

Discussion

10.	The value of COP in vapour compression cycle is usually__________________?
A.	always less than unity
B.	always more than unity
C.	equal to unity
D.	any one of the above
E.	none of the above
Answer» C. equal to unity

Discussion

11.	The suction pipe diameter of refrigerating unit compressor in comparison to delivery side is_________________?
A.	bigger
B.	smaller
C.	equal
D.	smaller/bigger depending on capacity
E.	unpredictable
Answer» B. smaller

Discussion

12.	The relative coefficient of performance is_____________________?
A.	actual COP/fheoretical COP
B.	theoretical COP/actual COP
C.	actual COP x theoretical COP
D.	1-actual COP x theoretical COP
E.	1-actual COP/fheoretical COP.
Answer» B. theoretical COP/actual COP

Discussion

13.	The refrigeration effect in a dry evaporator compared to flooded evaporator in a similar plant is_________________?
A.	same
B.	more
C.	less
D.	more or less depending on ambient conditions
E.	unpredictable
Answer» D. more or less depending on ambient conditions

Discussion

14.	The refrigerant for a refrigerator should have ___________________?
A.	high sensible heat
B.	high total heat
C.	high latent heat
D.	low latent heat
E.	low sensible heat
Answer» D. low latent heat

Discussion

15.	The moisture in a refrigerant is removed by___________________?
A.	evaporator
B.	safety relief valve
C.	dehumidifier
D.	driers
E.	expansion valve
Answer» E. expansion valve

Discussion

16.	The lower horizontal line of the refrigeration cycle plotted on pressure-enthalpy-diagram represents_____________________?
A.	condensation of the refrigerant vapour
B.	evaporation of the refrigerant liquid
C.	compression of the refrigerant vapour
D.	metering of the refrigerant liquid
E.	none of the above
Answer» C. compression of the refrigerant vapour

Discussion

17.	The leaks in a refrigeration system using Freon are detected by____________________?
A.	halide torch which on detection produces greenish flame lighting
B.	sulphur sticks which on detection gives white smoke
C.	using reagents
D.	smelling
E.	sensing reduction in pressure
Answer» B. sulphur sticks which on detection gives white smoke

Discussion

18.	The higher temperature in vapour compression cycle occurs at____________________?
A.	receiver
B.	expansion valve
C.	evaporator
D.	condenser discharge
E.	compressor discharge
Answer» F.

Discussion

19.	The general rule for rating refrigeration systems (excepting for C02 system) is to approximate following h.p. per ton of refrigeration__________________?
A.	0.1 to 0.5 h.p. per ton of refrigeration
B.	0.5 to 0.8 h.p. per ton of refrigeration
C.	1 to 2 h.p. per ton of refrigeration
D.	2 to 5 h.p. per ton of refrigeration
E.	5 to 10 h.p. per ton refrigeration
Answer» D. 2 to 5 h.p. per ton of refrigeration

Discussion

20.	The evolution of heat of solution takes place in ammonia absorption plant when _____________________?
A.	ammonia vapour goes into solution
B.	ammonia vapour is driven out of solution
C.	lithium bromide mixes with ammonia
D.	weak solution mixes with strong solution
E.	lithium bromide is driven out of solution
Answer» B. ammonia vapour is driven out of solution

Discussion

21.	The domestic refrigerator uses following type of compressor ____________________?
A.	centrifugal
B.	axial
C.	miniature sealed unit
D.	piston type reciprocating
E.	none of the above
Answer» E. none of the above

Discussion

22.	The COP of a vapor compression plant in comparison to vapor absorption plant is ________________?
A.	more
B.	less
C.	same
D.	more/less depending on size of plant
E.	unpredictable
Answer» B. less

Discussion

23.	The C.O.P. of a refrigeration cycle with lowering of condenser temperature, keeping the evaporator temperature constant, will__________________?
A.	increase
B.	decrease
C.	may increase or decrease depending on the type of refrigerant used
D.	remain unaffected
E.	unpredictable
Answer» B. decrease

Discussion

24.	The C.O.P of a refrigeration cycle with increase in evaporator temperature, keeping condenser temperature constant, will______________________?
A.	increase
B.	decrease
C.	remain unaffected
D.	may increase or decrease depending on the type of refrigerant used
E.	unpredictable
Answer» B. decrease

Discussion

25.	The COP of a domestic refrigerator___________________?
A.	is less than 1
B.	is more than 1
C.	is equal to 1
D.	depends upon the make
E.	depends upon the weather conditions
Answer» C. is equal to 1

Discussion

26.	The condensing pressure due to the presence of non-condensable gases, as compared to that actually required for condensing temperatures without non-condensable gases ____________________ ?
A.	will be higher
B.	will be lower
C.	will remain unaffected
D.	may be higher or lower depending upon the nature of non-condensable gases
E.	unpredictable
Answer» B. will be lower

Discussion

27.	The coefficient of performance is the ratio of the refrigerant effect to the_________________?
A.	heat of compression
B.	work done by compressor
C.	enthalpy increase in compressor
D.	all of the above
E.	none of the above
Answer» E. none of the above

Discussion

28.	The change in evaporator temperature in a refrigeration cycle, as compared to change in condenser temperature, influences the value of C.O.P_____________________?
A.	more
B.	less
C.	equally
D.	unpredictable
E.	none of the above
Answer» B. less

Discussion

29.	The boiling point of ammonia is___________________?
A.	-100°C
B.	-50°C
C.	– 33.3°C
D.	0°C
E.	33.3°C
Answer» D. 0°C

Discussion

30.	The bank of tubes at the back of domestic refrigerator are _________________?
A.	condenser tubes
B.	evaporator tubes
C.	refrigerant cooling tubes
D.	capillary tubes
E.	throttling device
Answer» B. evaporator tubes

Discussion

31.	The advantage of dry compression is that________________?
A.	it permits higher speeds to be used
B.	it permits complete evaporation in the evaporator
C.	it results in high volumetirc and mechanical efficiency
D.	all of the above
E.	none of the above
Answer» E. none of the above

Discussion

32.	Refrigeration in aeroplanes usually employs the following refrigerant___________________?
A.	Co2
B.	Freon-11
C.	Freon-22
D.	Air
E.	none of the above
Answer» E. none of the above

Discussion

33.	Reducing suction pressure in refrigeration cycle_________________?
A.	lowers evaporation temperature
B.	increases power required per ton of refrigeration
C.	lowers compressor capacity because vapour is lighter
D.	reduces weight displaced by piston
E.	all of the above
Answer» F.

Discussion

34.	Rating of a domestic refrigerator is of the order of__________________?
A.	0.1 ton
B.	5 tons
C.	10 tons
D.	40 tons
E.	100 tons
Answer» B. 5 tons

Discussion

35.	Presence of moisture in a refrigerant affects the working of___________________?
A.	compressor
B.	condenser
C.	evaparator
D.	expansion valve
E.	heat transfer
Answer» E. heat transfer

Discussion

36.	Pick up the incorrect statement?
A.	lithium bromide used in vapour absorption cycle is nonvolatile
B.	lithium bromide plant can’t operate below 0°C
C.	a separator is used in lithium bromide plant to remove the unwanted water vapour by condensing
D.	concentration of solution coming out of lithium bromide generator is more in comparison to that entering the generator
E.	weak solution in liquid heat exchanger gives up heat to the strong solution
Answer» D. concentration of solution coming out of lithium bromide generator is more in comparison to that entering the generator

Discussion

37.	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
E.	ammonia vapour to strong solution
Answer» C. strong solution to ammonia vapour

Discussion

38.	One ton refrigeratiqn corresponds to_________________?
A.	50 kcal/min
B.	50 kcal/kr
C.	80 kcal/min
D.	80 kcal/hr
E.	1000 kcal/day
Answer» B. 50 kcal/kr

Discussion

39.	One ton of the refrigeration is_________________?
A.	the standard unit used in refrigeration problems
B.	the cooling effect produced by melting 1 ton of ice
C.	the refrigeration effect to freeze 1 ton of water at 0°C into ice at 0°C in 24 hours
D.	the refrigeration effect to produce 1 ton of ice at NTP conditions
E.	the refrigeration effect to produce 1 ton of ice in 1 hour time
Answer» D. the refrigeration effect to produce 1 ton of ice at NTP conditions

Discussion

40.	One ton of refrigeration is equal to the refrigeration effect corresponding to melting of 1000 kg of ice_________________?
A.	in 1 hour
B.	in 1 minute
C.	in 24 hours
D.	in 12 hours
E.	in 10 hours
Answer» D. in 12 hours

Discussion

41.	One of the purposes of sub-cooling the liquid refrigerant is to________________?
A.	reduce compressor overheating
B.	reduce compressor discharge temperature
C.	increase cooling effect
D.	ensure that only liquid and not the vapour enters the expansion (throttling) valve
E.	none of the above
Answer» E. none of the above

Discussion

42.	On the pressure-enthalpy diagram, condensation and desuperheating is represented by a horizontal line because the process ________________?
A.	involves no change in volume
B.	takes place at constant temperature
C.	takes place at constant entropy
D.	takes place at constant enthalpy
E.	takes place at constant pressure
Answer» F.

Discussion

43.	Most of the domestic refrigerators work on the following refrigeration system _________________?
A.	vapour compression
B.	vapour absorption
C.	carnot cycle
D.	electrolux refrigerator
E.	dual cycle
Answer» B. vapour absorption

Discussion

44.	Moisture in freon refrigeration system causes________________?
A.	ineffective refrigeration
B.	high power consumption
C.	freezing automatic regulating valve
D.	corrosion of whole system
E.	breakdown of refrigerant
Answer» D. corrosion of whole system

Discussion

45.	Mass flow ratio of NH3 in comparison to Freon-12 for same refrigeration load and same temperature limits is of the order of___________________?
A.	1 : 1
B.	1 : 9
C.	9 : 1
D.	1 : 3
E.	3 : 1
Answer» C. 9 : 1

Discussion

46.	In vapour compression cycle, the conditii of refrigerant is saturated liquid________________?
A.	after passing through the condenser
B.	before passing through the condensei
C.	after passing through the expansion throttle valve
D.	before entering the expansion valve
E.	before entering the compressor
Answer» B. before passing through the condensei

Discussion

47.	In vapour compression cycle using NH3 as refrigerant, initial charge is filled at_________________?
A.	suction of compressor
B.	delivery of compressor
C.	high pressure side close to receiver
D.	low pressure side near receiver
E.	anywhere in the cycle
Answer» D. low pressure side near receiver

Discussion

48.	In vapour compression cycle the condition of refrigerant is superheated vapour _____________________?
A.	after passing through the condenser
B.	before passing through the condenser
C.	after passing through the expansion or throttle valve
D.	before [entering the expansion valve
E.	before entering the compressor
Answer» C. after passing through the expansion or throttle valve

Discussion

49.	In vapor compression refrigeration system, refrigerant occurs as liquid between_________________?
A.	condenser and expansion valve
B.	compressor and evaporator
C.	expansion valve and evaporator
D.	compressor and condenser
E.	none of the above
Answer» D. compressor and condenser

Discussion

50.	In vapor compression cycle the condition off refrigerant is dry saturated vapor________________?
A.	after passing through the condenser
B.	before passing through the condenser
C.	after passing through the expansion or throttle valve
D.	before entering the expansion valve
E.	before entering the compressor
Answer» F.

Discussion

Explore topic-wise MCQs in Mechanical Engineering Questions.

Which of the following refrigerants has lowest freezing point_______________?

Which of the following is not a desirable property of a refrigerant_________________?

Which of the following cycles uses air as the refrigerant__________________?

Where does the lowest temperature occur in a vapour compression cycle ?

Vertical lines on pressure-enthalpy chart show constant_______________?

Vapor compression refrigeration is some what like ____________________?

Under-cooling in a refrigeration cycle_________________?

The vapor pressure of refrigerant should be_________________?

The vapor compression refrigerator employs the following cycle_________________?

The value of COP in vapour compression cycle is usually__________________?

The suction pipe diameter of refrigerating unit compressor in comparison to delivery side is_________________?

The relative coefficient of performance is_____________________?

The refrigeration effect in a dry evaporator compared to flooded evaporator in a similar plant is_________________?

The refrigerant for a refrigerator should have ___________________?

The moisture in a refrigerant is removed by___________________?

The lower horizontal line of the refrigeration cycle plotted on pressure-enthalpy-diagram represents_____________________?

The leaks in a refrigeration system using Freon are detected by____________________?

The higher temperature in vapour compression cycle occurs at____________________?

The general rule for rating refrigeration systems (excepting for C02 system) is to approximate following h.p. per ton of refrigeration__________________?

The evolution of heat of solution takes place in ammonia absorption plant when _____________________?

The domestic refrigerator uses following type of compressor ____________________?

The COP of a vapor compression plant in comparison to vapor absorption plant is ________________?

The C.O.P. of a refrigeration cycle with lowering of condenser temperature, keeping the evaporator temperature constant, will__________________?

The C.O.P of a refrigeration cycle with increase in evaporator temperature, keeping condenser temperature constant, will______________________?

The COP of a domestic refrigerator___________________?

The condensing pressure due to the presence of non-condensable gases, as compared to that actually required for condensing temperatures without non-condensable gases ____________________ ?

The coefficient of performance is the ratio of the refrigerant effect to the_________________?

The change in evaporator temperature in a refrigeration cycle, as compared to change in condenser temperature, influences the value of C.O.P_____________________?

The boiling point of ammonia is___________________?

The bank of tubes at the back of domestic refrigerator are _________________?

The advantage of dry compression is that________________?

Refrigeration in aeroplanes usually employs the following refrigerant___________________?

Reducing suction pressure in refrigeration cycle_________________?

Rating of a domestic refrigerator is of the order of__________________?

Presence of moisture in a refrigerant affects the working of___________________?

Pick up the incorrect statement?

Pick up the correct statement about giving up of heat from one medium to other in ammonia absorption system ?

One ton refrigeratiqn corresponds to_________________?

One ton of the refrigeration is_________________?

One ton of refrigeration is equal to the refrigeration effect corresponding to melting of 1000 kg of ice_________________?

One of the purposes of sub-cooling the liquid refrigerant is to________________?

On the pressure-enthalpy diagram, condensation and desuperheating is represented by a horizontal line because the process ________________?

Most of the domestic refrigerators work on the following refrigeration system _________________?

Moisture in freon refrigeration system causes________________?

Mass flow ratio of NH3 in comparison to Freon-12 for same refrigeration load and same temperature limits is of the order of___________________?

In vapour compression cycle, the conditii of refrigerant is saturated liquid________________?

In vapour compression cycle using NH3 as refrigerant, initial charge is filled at_________________?

In vapour compression cycle the condition of refrigerant is superheated vapour _____________________?

In vapor compression refrigeration system, refrigerant occurs as liquid between_________________?

In vapor compression cycle the condition off refrigerant is dry saturated vapor________________?