In vapor compression cycle, the condition of refrigerant is very wet vapor________________?

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 of refrigerant is high pressure saturated liquid________________?

after passing through the condenser

before passing through the condenser

after passing through the expansion or thiottle valve

before entering the expansion valve

In refrigerators, the temperature difference between the evaporating refrigerant and the medium being cooled should be_________________?

as low as possible (3 to 11°C)

In a refrigeration system, heat absorbed in comparison to heat rejected is_________________?

more for small capacity and less for high capacity

less for small capacity and more for high capacity

In a flooded evaporator refrigerator, an accumulator at suction of compressor is used to___________________?

collect liquid refrigerant and prevent it from going to compressor

Highest temperature encountered in refrigeration cycle should be________________?

near critical temperature of refrigerant

much below critical temperature

Highest pressure encountered in a refrigeration system should be________________?

critical pressure of refrigerant

Formation of frost on evaporator in refrigerator ________________?

results in loss of heat due to poor heat transfer

can be avoided by proper design

For proper refrigeration in a cabinet, if the temperature and vapour pressure difference between cabinet and atmosphere is high, then_________________?

refrigerant with lower evaporation temperature should be used

perfectly tight vapour seal should be used

refrigerant with lower evaporation temperature should be used

refrigerant with high boiling point must be used

For better COP of refrigerator, the pressure range corresponding to temperature in evaporator and condenser must be____________________?

under some conditions small and under some conditions high

Domestic refrigerator working on vapour compression cycle uses the following type of expansion device____________________?

electrically operated throttling valve

Critical pressure of a liquid is the pressure_________________?

above which liquid will remain liquid

above which liquid becomes vapour

above which liquid becomes solid

at which all the three phases exist together

Cooling water is required for following equipment in ammonia absorption plant__________________?

condenser, absorber and separator (rectifier)

Condensing temperature in a refrigerator is the temperature_________________?

at which refrigerant gas becomes liquid

Clapeyron equation is a relation between___________________?

temperature, pressure and enthalpy

temperature, pressure, and specil volume

temperature, pressure, specific volur and’enthalpy

An important characteristic of absorption system of refrigeration is__________________?

its input only in the form of heating

Ammonia-absorption refrigeration cycle requires__________________?

nearly same work input as for vapour compression cycle

Allowable pressure on high-pressure side or ammonia absorption system is of the order of_________________?

slightly above atmospheric pressure

A standard ice point temperature corresponds to the temperature of ___________________?

mixture of ice, water and vapour under equilibrium conditions under NTP conditions

mixture of ice and water Under equilibrium conditions

A refrigerant should have _____________________?_x005F_x000D_Pick up the wrong statement ?

high latent heat of vaporisation

89 + Mcqs in Refrigeration Page 2 McqOptions

51.	In vapor compression cycle, the condition of refrigerant is very wet 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

52.	In vapor compression cycle, the condition of refrigerant is high pressure saturated liquid________________?
A.	after passing through the condenser
B.	before passing through the condenser
C.	after passing through the expansion or thiottle valve
D.	before entering the expansion valve
E.	before entering the compressor
Answer» E. before entering the compressor

Discussion

53.	In S.J. unit, one ton of refrigeration is equal to___________________?
A.	210 kJ/min
B.	21 kJ/min
C.	420 kJ/min
D.	840 kJ/min
E.	105 kJ/min
Answer» B. 21 kJ/min

Discussion

54.	In refrigerators, the temperature difference between the evaporating refrigerant and the medium being cooled should be_________________?
A.	high, of the order of 25°
B.	as low as possible (3 to 11°C)
C.	zero
D.	any value
E.	none of the above
Answer» C. zero

Discussion

55.	In refrigerator, liquid receiver is required between condenser and flow controlling device, if quantity of refrigerant for system is_____________________?
A.	less than 2 kg
B.	more than or equal to 3.65 kg
C.	more than 10 kg
D.	there is no such consideration
E.	pone of the above
Answer» C. more than 10 kg

Discussion

56.	In a vapor compression cycle, the refrigerant immediately after expansion valve is___________________?
A.	liquid
B.	sub-cooled liquid
C.	saturated liquid
D.	wet vapour
E.	dry vapour
Answer» E. dry vapour

Discussion

57.	In a refrigeration system, heat absorbed in comparison to heat rejected is_________________?
A.	more
B.	less
C.	same
D.	more for small capacity and less for high capacity
E.	less for small capacity and more for high capacity
Answer» C. same

Discussion

58.	In a refrigeration cycle, the flow of refrigerant is controlled by___________________?
A.	compressor
B.	condenser
C.	evaporator
D.	expansion valve
E.	all of the above
Answer» E. all of the above

Discussion

59.	In a flooded evaporator refrigerator, an accumulator at suction of compressor is used to___________________?
A.	collect liquid refrigerant and prevent it from going to compressor
B.	detect liquid in vapour
C.	superheat the vapour
D.	collect vapours
E.	increase refrigeration effect
Answer» B. detect liquid in vapour

Discussion

60.	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
E.	unpredictable
Answer» C. less

Discussion

61.	If a heat pump cycle operates between the condenser temperature of +27°C and evaporator temperature of – 23°C, then the Carnot COP will be_________________?
A.	0.2
B.	1.2
C.	5
D.	6
E.	10
Answer» E. 10

Discussion

62.	Highest temperature encountered in refrigeration cycle should be________________?
A.	near critical temperature of refrigerant
B.	above critical temperature
C.	at critica. temperature
D.	much below critical temperature
E.	could be anywhere
Answer» E. could be anywhere

Discussion

63.	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
E.	there is no such restriction
Answer» C. much above critical pressure

Discussion

64.	Freon group of refrigerants are___________________?
A.	inflammable
B.	toxic
C.	non-inflammable and toxic
D.	non-toxic and inflammable
E.	non-toxic and non-inflammable
Answer» F.

Discussion

65.	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
E.	decreases compressor power
Answer» B. increases heat transfer rate

Discussion

66.	For proper refrigeration in a cabinet, if the temperature and vapour pressure difference between cabinet and atmosphere is high, then_________________?
A.	bigger cabinet should be used
B.	smaller cabinet should be used
C.	perfectly tight vapour seal should be used
D.	refrigerant with lower evaporation temperature should be used
E.	refrigerant with high boiling point must be used
Answer» D. refrigerant with lower evaporation temperature should be used

Discussion

67.	For obtaining high COP, the pressure range of compressor should be_______________?
A.	high
B.	low
C.	optimum
D.	any value
E.	there is no such criterion
Answer» C. optimum

Discussion

68.	For better COP of refrigerator, the pressure range corresponding to temperature in evaporator and condenser must be____________________?
A.	small
B.	high
C.	equal
D.	anything
E.	under some conditions small and under some conditions high
Answer» B. high

Discussion

69.	Efficiency of a Carnot engine is given as 80%. If the- cycle direction be reversed, what will be the value of COP of reversed Carnot cycle_________________?
A.	1.25
B.	0.8
C.	0.5
D.	0.25
E.	none of the above
Answer» E. none of the above

Discussion

70.	Domestic refrigerator working on vapour compression cycle uses the following type of expansion device____________________?
A.	electrically operated throttling valve
B.	manually operated valve
C.	thermostatic valve
D.	capillary tube
E.	expansion valve
Answer» E. expansion valve

Discussion

71.	Critical temperature is’ the temperature above which _____________________?
A.	a gas will never liquefy
B.	a gas will immediately liquefy
C.	water will evaporate
D.	water will never evaporate
E.	none of the above
Answer» B. a gas will immediately liquefy

Discussion

72.	Critical pressure of a liquid is the pressure_________________?
A.	above which liquid will remain liquid
B.	above which liquid becomes gas
C.	above which liquid becomes vapour
D.	above which liquid becomes solid
E.	at which all the three phases exist together
Answer» B. above which liquid becomes gas

Discussion

73.	Cooling water is required for following equipment in ammonia absorption plant__________________?
A.	condenser
B.	evaporator
C.	absorber
D.	condenser and absorber
E.	condenser, absorber and separator (rectifier)
Answer» F.

Discussion

74.	Condensing temperature in a refrigerator is the temperature_________________?
A.	of cooling medium
B.	of freezing zone
C.	of evaporator
D.	at which refrigerant gas becomes liquid
E.	condensing temperature of ice
Answer» E. condensing temperature of ice

Discussion

75.	Clapeyron equation is applicable for registration at___________________?
A.	saturation point of vapor
B.	saturation point of liquid
C.	sublimation temperature
D.	triple point
E.	critical point
Answer» B. saturation point of liquid

Discussion

76.	Clapeyron equation is a relation between___________________?
A.	temperature, pressure and enthalpy
B.	specific volume and enthalpy
C.	temperature and enthalpy
D.	temperature, pressure, and specil volume
E.	temperature, pressure, specific volur and’enthalpy
Answer» F.

Discussion

77.	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
E.	none of the above
Answer» C. remains same

Discussion

78.	Aqua ammonia is used as refrigerant in the following type of refrigeration system_________________?
A.	compression
B.	direct
C.	indirect
D.	absorption
E.	none of the above
Answer» E. none of the above

Discussion

79.	An important characteristic of absorption system of refrigeration is__________________?
A.	noisy operation
B.	quiet operation
C.	cooling below 0°C
D.	very little power consumption
E.	its input only in the form of heating
Answer» C. cooling below 0°C

Discussion

80.	Ammonia is __________________?
A.	non-toxic
B.	non-inflammable
C.	toxic and non-inflammable
D.	highly toxic and inflammable
E.	none of the above
Answer» E. none of the above

Discussion

81.	Ammonia-absorption refrigeration cycle requires__________________?
A.	very little work input
B.	maximum work input
C.	nearly same work input as for vapour compression cycle
D.	zero work input
E.	none of the above
Answer» B. maximum work input

Discussion

82.	Allowable pressure on high-pressure side or ammonia absorption system is of the order of_________________?
A.	atmospheric pressure
B.	slightly above atmospheric pressure
C.	2-4 bars
D.	5-6 bars
E.	7-10 bars
Answer» E. 7-10 bars

Discussion

83.	Air refrigeration operates on_____________________?
A.	Carnot cycle
B.	Reversed Carnot cycle
C.	Rankine cycle
D.	Erricson cycle
E.	Brayton cycle
Answer» F.

Discussion

84.	Air refrigeration cycle is used in ____________________?
A.	domestic refrigerators
B.	commercial refrigerators
C.	air conditioning
D.	gas liquefaction
E.	such a cycle does not exist
Answer» E. such a cycle does not exist

Discussion

85.	Accumulators should have adequate volume to store refrigerant charge at least_________________?
A.	10%
B.	25%
C.	50%
D.	75%
E.	100%
Answer» D. 75%

Discussion

86.	Absorption system normally uses the following refrigerant___________________?
A.	Freon-11
B.	Freon-22
C.	C02
D.	S02
E.	ammonia
Answer» F.

Discussion

87.	A standard ice point temperature corresponds to the temperature of ___________________?
A.	water at 0°C
B.	ice at – 4°C
C.	solid and dry ice
D.	mixture of ice, water and vapour under equilibrium conditions under NTP conditions
E.	mixture of ice and water Under equilibrium conditions
Answer» F.

Discussion

88.	A refrigeration cycle operates between condenser temperature of + 27°C and evaporator temperature of- 23°C. The Cannot coefficient of performance of cycle will be_________________?
A.	0.2
B.	1.2
C.	5
D.	6
E.	10
Answer» D. 6

Discussion

89.	A refrigerant should have _____________________?_x005F_x000D_Pick up the wrong statement ?
A.	Tow specific heat of liquid
B.	high boiling point
C.	high latent heat of vaporisation
D.	higher critical temperature
E.	low specific volume of vapour
Answer» C. high latent heat of vaporisation

Discussion

Explore topic-wise MCQs in Mechanical Engineering Questions.

In vapor compression cycle, the condition of refrigerant is very wet vapor________________?

In vapor compression cycle, the condition of refrigerant is high pressure saturated liquid________________?

In S.J. unit, one ton of refrigeration is equal to___________________?

In refrigerators, the temperature difference between the evaporating refrigerant and the medium being cooled should be_________________?

In refrigerator, liquid receiver is required between condenser and flow controlling device, if quantity of refrigerant for system is_____________________?

In a vapor compression cycle, the refrigerant immediately after expansion valve is___________________?

In a refrigeration system, heat absorbed in comparison to heat rejected is_________________?

In a refrigeration cycle, the flow of refrigerant is controlled by___________________?

In a flooded evaporator refrigerator, an accumulator at suction of compressor is used to___________________?

If the evaporator temperature of a plant is lowered, keeping the condenser temperature constant, the h.p. of compressor required will be________________?

If a heat pump cycle operates between the condenser temperature of +27°C and evaporator temperature of – 23°C, then the Carnot COP will be_________________?

Highest temperature encountered in refrigeration cycle should be________________?

Highest pressure encountered in a refrigeration system should be________________?

Freon group of refrigerants are___________________?

Formation of frost on evaporator in refrigerator ________________?

For proper refrigeration in a cabinet, if the temperature and vapour pressure difference between cabinet and atmosphere is high, then_________________?

For obtaining high COP, the pressure range of compressor should be_______________?

For better COP of refrigerator, the pressure range corresponding to temperature in evaporator and condenser must be____________________?

Efficiency of a Carnot engine is given as 80%. If the- cycle direction be reversed, what will be the value of COP of reversed Carnot cycle_________________?

Domestic refrigerator working on vapour compression cycle uses the following type of expansion device____________________?

Critical temperature is’ the temperature above which _____________________?

Critical pressure of a liquid is the pressure_________________?

Cooling water is required for following equipment in ammonia absorption plant__________________?

Condensing temperature in a refrigerator is the temperature_________________?

Clapeyron equation is applicable for registration at___________________?

Clapeyron equation is a relation between___________________?

At lower temperatures and pressures, the latent heat of vaporisation of a refrigerant_________________?

Aqua ammonia is used as refrigerant in the following type of refrigeration system_________________?

An important characteristic of absorption system of refrigeration is__________________?

Ammonia is __________________?

Ammonia-absorption refrigeration cycle requires__________________?

Allowable pressure on high-pressure side or ammonia absorption system is of the order of_________________?

Air refrigeration operates on_____________________?

Air refrigeration cycle is used in ____________________?

Accumulators should have adequate volume to store refrigerant charge at least_________________?

Absorption system normally uses the following refrigerant___________________?

A standard ice point temperature corresponds to the temperature of ___________________?

A refrigeration cycle operates between condenser temperature of + 27°C and evaporator temperature of- 23°C. The Cannot coefficient of performance of cycle will be_________________?

A refrigerant should have _____________________?_x005F_x000D_Pick up the wrong statement ?