Co-efficient of Performance (COP) of a refrigerator is the ratio of the (A) Work required to refrigeration obtained (B) Refrigeration obtained to the work required (C) Lower to higher temperature (D) Higher to lower temperature

Co-efficient of Performance (COP) of a refrigerator is the ratio of the (A) Work required to refrigeration obtained
(B) Refrigeration obtained to the work required
(C) Lower to higher temperature
(D) Higher to lower temperature
by

1 Answer

Answer :

(B) Refrigeration obtained to the work required
by

Related questions

The co-efficient of performance (COP) of a refrigerating system, which is its index of performance, is defined as the ratio of useful refrigeration to the net work. The units of __________ and COP are the same. (A) Kinematic viscosity (B) Work (C) Temperature (D) None of these

Description : The co-efficient of performance (COP) of a refrigerating system, which is its index of performance, is defined as the ratio of useful refrigeration to the net work. The units of __________ and COP are the same. (A) Kinematic viscosity (B) Work (C) Temperature (D) None of these

Last Answer : (D) None of these

Out of the following refrigeration cycles, which one has the minimum COP (Co-efficient of performance)? (A) Air cycle (B) Carnot cycle (C) Ordinary vapour compression cycle (D) Vapour compression with a reversible expansion engine

Description : Out of the following refrigeration cycles, which one has the minimum COP (Co-efficient of performance)? (A) Air cycle (B) Carnot cycle (C) Ordinary vapour compression cycle (D) Vapour compression with a reversible expansion engine

Last Answer : A) Air cycle

The thermal efficiency of a reversible heat engine operating between two given thermal reservoirs is 0.4. The device is used either as a refrigerator or as a heat pump between the same reservoirs. Then the coefficient of performance as a refrigerator (COP)R and the co-efficient of performance as a heat pump (COP)HP are (A) (COP)R = (COP)HP = 0.6 (B) (COP)R = 2.5; (COP)HP = 1.5 (C) (COP)R = 1.5; (COP)HP = 2.5 (D) (COP)R = (COP)HP = 2.5

Description : The thermal efficiency of a reversible heat engine operating between two given thermal reservoirs is 0.4. The device is used either as a refrigerator or as a heat pump between the same reservoirs. Then the coefficient of performance as a ... )R = 1.5; (COP)HP = 2.5 (D) (COP)R = (COP)HP = 2.5

Last Answer : (C) (COP)R = 1.5; (COP)HP = 2.5

The Carnot co-efficient of performance (COP) of a domestic air conditioner compared to a household refrigerator is (A) Less (B) More (C) Same (D) Dependent on climatic conditions

Description : The Carnot co-efficient of performance (COP) of a domestic air conditioner compared to a household refrigerator is (A) Less (B) More (C) Same (D) Dependent on climatic conditions

Last Answer : (A) Less

A refrigerator is working on reversed carnot cycle between temperature of 30°C to –10°C with capacity of 10 tonnes. Calculate. (i) The COP (ii) Define ton of refrigeration (iii) Give the industrial application of refrigeration

Description : A refrigerator is working on reversed carnot cycle between temperature of 30°C to –10°C with capacity of 10 tonnes. Calculate. (i) The COP (ii) Define ton of refrigeration (iii) Give the industrial application of refrigeration

Last Answer : (ii) Ton of refrigeration: It is defined as the quantity of heat required to be removed from 1Ton water at 0oC to get ice at 0oC in one day. (iii) Industrial applications of refrigeration ... food stuff such as meat, fruit, fruit juice, vegetables etc. 5. Ice cooling of concrete for dam.

COP of a refrigerator drawing 1 kW of power per ton of refrigeration is about (A) 0.5 (B) 3.5 (C) 4.5 (D) 8.5

Description : COP of a refrigerator drawing 1 kW of power per ton of refrigeration is about (A) 0.5 (B) 3.5 (C) 4.5 (D) 8.5

Last Answer : (B) 3.5

Pick out the wrong statement. (A) A refrigeration cycle violates the second law of thermodynamics (B) Refrigeration cycle is normally represented by a temperature vs. entropy plot (C) In a refrigerator, work required decreases as the temperature of the refrigerator and the temperature at which heat is rejected increases (D) One ton of refrigeration is equivalent to the rate of heat absorption equal to 3.53 kW

Description : Pick out the wrong statement. (A) A refrigeration cycle violates the second law of thermodynamics (B) Refrigeration cycle is normally represented by a temperature vs. entropy plot (C) In a refrigerator, ... (D) One ton of refrigeration is equivalent to the rate of heat absorption equal to 3.53 kW

Last Answer : (A) A refrigeration cycle violates the second law of thermodynamics

Co-efficient of performance of a Carnot cycle refrigerator operating between - 23°C and + 27°C is (A) 3 (B) 5 (C) 0.5 (D) 1.5

Description : Co-efficient of performance of a Carnot cycle refrigerator operating between - 23°C and + 27°C is (A) 3 (B) 5 (C) 0.5 (D) 1.5

Last Answer : Option A

The coefficient of performance (COP) is the ratio between the:  A. Power consumption in watts and heat absorbed per hour  B. Heat absorbed per hour and the power consumption in watts  C. Work required and the absorbed heat  D. Absorbed heat and work required

Description : The coefficient of performance (COP) is the ratio between the:  A. Power consumption in watts and heat absorbed per hour  B. Heat absorbed per hour and the power consumption in watts  C. Work required and the absorbed heat  D. Absorbed heat and work required

Last Answer : Absorbed heat and work required

Pick out the wrong statement. (A) The condensing film co-efficient is about 3 times lower for vertical condenser as compared to the equivalent horizontal condenser for identical situation (B) Film co-efficient for vaporisation decreases as a result of vapor binding (C) In industrial practice, sub-cooling of condensate is required, when thecondensate is a volatile liquid and is to be transferred for storage(D) Overall heat transfer co-efficient in a heat exchanger is controlled by thevalue of the film co-efficient, which is higher

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Last Answer : (D) Overall heat transfer co-efficient in a heat exchanger is controlled by the value of the film co-efficient, which is higher

Lowering of condenser temperature (keeping the evaporator temperature constant) in case of vapour compression refrigeration system results in (A) Increased COP (B) Same COP (C) Decreased COP (D) Increased or decreased COP; depending upon the type of refrigerant

Description : Lowering of condenser temperature (keeping the evaporator temperature constant) in case of vapour compression refrigeration system results in (A) Increased COP (B) Same COP (C) Decreased COP (D) Increased or decreased COP; depending upon the type of refrigerant

Last Answer : (A) Increased COP

What is the value of maximum COP in case of absorption refrigeration, if refrigeration provided is at temperature, TR (where, T1 and T2 are source & surrounding temperatures respectively.)? (A) TR/(T2 - TR) × (T1 - T2 )/T1 (B) TR/(T2 - TR) × T1 /(T1 - T2 ) (C) TR/(T1 - TR) × (T1 - T2 )/T1 (D) None of these

Description : What is the value of maximum COP in case of absorption refrigeration, if refrigeration provided is at temperature, TR (where, T1 and T2 are source & surrounding temperatures respectively.)? (A) TR/(T2 - TR) (T1 - T2 )/T1 (B) TR ... T1 /(T1 - T2 ) (C) TR/(T1 - TR) (T1 - T2 )/T1 (D) None of these

Last Answer : (A) TR/(T2 - TR) × (T1 - T2 )/T1

The effect of changing the evaporator temperature on COP as compared to that of changing the condenser temperature (in vapour compression refrigeration system) is (A) Less pronounced (B) More pronounced (C) Equal (D) Data insufficient, can't be predicted

Description : The effect of changing the evaporator temperature on COP as compared to that of changing the condenser temperature (in vapour compression refrigeration system) is (A) Less pronounced (B) More pronounced (C) Equal (D) Data insufficient, can't be predicted

Last Answer : (B) More pronounced

In vapour compression refrigeration system, if the evaporator temperature and the condenser temperatures are -13°C and 37°C respectively, the Carnot COP will be (A) 5.2 (B) 6.2 (C) 0.168 (D) Data insufficient, can't be found out

Description : In vapour compression refrigeration system, if the evaporator temperature and the condenser temperatures are -13°C and 37°C respectively, the Carnot COP will be (A) 5.2 (B) 6.2 (C) 0.168 (D) Data insufficient, can't be found out

Last Answer : A) 5.2

Condensing film co-efficient for steam on horizontal tubes ranges from 5000 to 15000 Kcal/hr.m2 .°C. Condensation of vapor is carried out inside the tube in a shell and tube heat exchanger, when the (A) Higher condensing film co-efficient is desired (B) Condensate is corrosive in nature (C) Lower pressure drop through the exchanger is desired (D) Temperature of the incoming vapor is very high Answer: Option B

Description : Condensing film co-efficient for steam on horizontal tubes ranges from 5000 to 15000 Kcal/hr.m2 .°C. Condensation of vapor is carried out inside the tube in a shell and tube heat ... drop through the exchanger is desired (D) Temperature of the incoming vapor is very high

Last Answer : (B) Supersaturated

Which of the following has the minimum value of COP for a given refrigeration effect? (A) Reverse Carnot cycle (B) Ordinary vapour-compression cycle (C) Vapour-compression process with a reversible expansion engine (D) Air refrigeration cycle

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Last Answer : (D) Air refrigeration cycle

Out of the following refrigeration cycles, which one has maximum COP? (A) Air cycle (B) Carnot cycle (C) Ordinary vapor compression cycle (D) Vapor compression with a reversible expansion engin

Description : Out of the following refrigeration cycles, which one has maximum COP? (A) Air cycle (B) Carnot cycle (C) Ordinary vapor compression cycle (D) Vapor compression with a reversible expansion engin

Last Answer : (B) Carnot cycle

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

Description : 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

Last Answer : Ans: a

. A dilute aqueous solution is to be concentrated in an evaporator system. High pressure steam is available. Multiple effect evaporator system is employed, because (A) Total heat transfer area of all the effects is -less than that in a single effect evaporator system (B) Total amount of vapor produced per Kg of feed steam in a multiple effect system is much higher than in a single effect (C) Boiling point elevation in a single effect system is much higher than that in any effect in a multi-effect system (D) Heat transfer co-efficient in a single effect is much lower than that in any effect in a multi-effect system

Description : . A dilute aqueous solution is to be concentrated in an evaporator system. High pressure steam is available. Multiple effect evaporator system is employed, because (A) Total heat transfer area of ... in a single effect is much lower than that in any effect in a multi-effect system

Last Answer : (B) Total amount of vapor produced per Kg of feed steam in a multiple effect system is much higher than in a single effect

The advantage of using a 1 - 2 shell and tube heat exchanger over a 1 - 1 shell and tube heat exchanger is (A) Lower tube side pressure drop (B) Lower shell side pressure drop (C) Higher tube side heat transfer co-efficient (D) Higher shell side heat transfer co-efficient

Description : The advantage of using a 1 - 2 shell and tube heat exchanger over a 1 - 1 shell and tube heat exchanger is (A) Lower tube side pressure drop (B) Lower shell side pressure drop (C) Higher tube side heat transfer co-efficient (D) Higher shell side heat transfer co-efficient

Last Answer : (C) Higher tube side heat transfer co-efficient

Under-cooling in a refrigeration cycle (a) increases COP (b) decreases COF (c) COP remains unaltered (d) other factors decide COP

Description : Under-cooling in a refrigeration cycle (a) increases COP (b) decreases COF (c) COP remains unaltered (d) other factors decide COP

Last Answer : Ans: a

Superheating in a refrigeration cycle (a) increases COP (b) decreases COP (c) COP remains unaltered (d) other factors decide COP

Description : Superheating in a refrigeration cycle (a) increases COP (b) decreases COP (c) COP remains unaltered (d) other factors decide COP

Last Answer : Ans: b

What is the use of flash chamber in a vapour compression refrigeration cycle to improve the COP of refrigeration cycle ?

Description : What is the use of flash chamber in a vapour compression refrigeration cycle to improve the COP of refrigeration cycle ?

Last Answer : When liquid refrigerant as obtained from condenser is throttled, there are some vapours. These vapours if carried through the evaporator will not contribute to refrigerating effect. Using a flash ... out in stages. Similarly compression process is also done in two separate compressor stages.

Which one is the correct relation between energy efficiency ratio (EER) and coefficient of performance (COP)?  A. EER = 2.34 COP  B. EER = 3.24 COP  C. EER = 3.42 COP  D. EER = 4.23 COP

Description : Which one is the correct relation between energy efficiency ratio (EER) and coefficient of performance (COP)?  A. EER = 2.34 COP  B. EER = 3.24 COP  C. EER = 3.42 COP  D. EER = 4.23 COP

Last Answer : EER = 3.42 COP

In a working refrigerator, the value of COP is always (A) 0 (B) < 0 (C) < 1 (D) > 1

Description : In a working refrigerator, the value of COP is always (A) 0 (B) < 0 (C) < 1 (D) > 1

Last Answer : (D) > 1

Refrigeration capacity of a household refrigerator may be round about __________ tons.(A) 0.15 (B) 1.5 (C) 4.5 (D) 6.5

Description : Refrigeration capacity of a household refrigerator may be round about __________ tons. (A) 0.15 (B) 1.5 (C) 4.5 (D) 6.5

Last Answer : (A) 0.15

Domestic refrigerator usually works on the __________ refrigeration cycle. (A) Carnot (B) Air (C) Absorption (D) vapour-ejection

Description : Domestic refrigerator usually works on the __________ refrigeration cycle. (A) Carnot (B) Air (C) Absorption (D) vapour-ejection

Last Answer : (C) Absorption

Which of the following units is not present in both the vapor compression refrigeration system and absorption refrigeration system? (A) Expansion valve (B) Condenser (C) Refrigerator (D) Compressor

Description : Which of the following units is not present in both the vapor compression refrigeration system and absorption refrigeration system? (A) Expansion valve (B) Condenser (C) Refrigerator (D) Compressor

Last Answer : (D) Compressor

Most of the domestic refrigerators work on the following refrigeration system (a) vapour compression (b) vapour absorption (c) carnot cycle (d) electrolux refrigerator

Description : Most of the domestic refrigerators work on the following refrigeration system (a) vapour compression (b) vapour absorption (c) carnot cycle (d) electrolux refrigerator

Last Answer : Ans: a

In thermodynamics, a throttling process, also called a _________, is a type of isenthalpic process where a liquid or gas is cooled as it passes from a higher pressure state to a lower pressure state.  a. Rankine Process  b. Carnot Cycle  c. Joule-Thomson process  d. Refrigeration process

Description : In thermodynamics, a throttling process, also called a _________, is a type of isenthalpic process where a liquid or gas is cooled as it passes from a higher pressure state to a lower pressure state.  a. Rankine Process  b. Carnot Cycle  c. Joule-Thomson process  d. Refrigeration process

Last Answer : Joule-Thomson process

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 weather conditions.

Description : 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 weather conditions.

Last Answer : Ans: b

A refrigeration cycle operates between condenser temperature of + 27°C and evaporator temperature of- 23°C. TheCarnot coefficient of performance of cycle will be (a) 0.2 (b) 1.2 (c) 5 (d) 6

Description : A refrigeration cycle operates between condenser temperature of + 27°C and evaporator temperature of- 23°C. TheCarnot coefficient of performance of cycle will be (a) 0.2 (b) 1.2 (c) 5 (d) 6

Last Answer : Ans: c

Co-efficient of performance for a reversed Carnot cycle working between temperatures T1 and T2(T1 > T2) is (A) T2/(T1- T2) (B) T1/(T1- T2) (C) (T1- T2)/T1 (D) (T1- T2)/T2

Description : Co-efficient of performance for a reversed Carnot cycle working between temperatures T1 and T2(T1 > T2) is (A) T2/(T1- T2) (B) T1/(T1- T2) (C) (T1- T2)/T1 (D) (T1- T2)/T2

Last Answer : (A) T2/(T1- T2)

The efficiency of a Carnot heat engine operating between absolute temperatures T1 and T2 (when, T1 > T2) is given by (T1- T2)/T1. The co efficient of performance (C.O.P.) of a Carnot heat pump operating between T1 and T2is given by (A) T1/(T1-T2) (B) T2/(T1-T2) (C) T1/T2 (D) T2/R1

Description : The efficiency of a Carnot heat engine operating between absolute temperatures T1 and T2 (when, T1 > T2) is given by (T1- T2)/T1. The co efficient of performance (C.O.P.) of a Carnot heat pump operating between T1 and T2is given by (A) T1/(T1-T2) (B) T2/(T1-T2) (C) T1/T2 (D) T2/R1

Last Answer : (A) T1/(T1-T2)

The efficiency of a Carnot heat engine operating between absolute temperatures T1 and T2(when, T1 > T2) is given by (T1- T2)/T1. The co efficient of performance (CO.P.) of a Carnot heat pump operating between T1 and T2is given by (A) T1/(T1-T2) (B) T2/(T1-T2) (C) T1/T2 (D) T2/T1

Description : The efficiency of a Carnot heat engine operating between absolute temperatures T1 and T2(when, T1 > T2) is given by (T1- T2)/T1. The co efficient of performance (CO.P.) of a Carnot heat pump operating between T1 and T2is given by (A) T1/(T1-T2) (B) T2/(T1-T2) (C) T1/T2 (D) T2/T1

Last Answer : (B) T2/(T1-T2)

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) increase refrigeration effect

Description : 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) increase refrigeration effect

Last Answer : Ans: a

Joule-Thomson co-efficient is the ratio of (A) Pressure change to temperature change occuring during adiabatic compression of a gas (B) Pressure change to temperature change occuring during adiabatic throttling of a gas (C) Temperature change to pressure change occuring during adiabatic compression of a gas (D) Temperature change to pressure change occuring during adiabatic throttling of a gas

Description : Joule-Thomson co-efficient is the ratio of (A) Pressure change to temperature change occuring during adiabatic compression of a gas (B) Pressure change to temperature change occuring during adiabatic ... a gas (D) Temperature change to pressure change occuring during adiabatic throttling of a gas

Last Answer : (D) Temperature change to pressure change occuring during adiabatic throttling of a gas

Range of compressibility co-efficient of the commercial compressible cake obtained in filtration operation is (A) 0.01 to 0.1(B) 0.1 to 0.3 (C) 0.2 to 0.8 (D) 0.2 to 0.4

Description : Range of compressibility co-efficient of the commercial compressible cake obtained in filtration operation is (A) 0.01 to 0.1 (B) 0.1 to 0.3 (C) 0.2 to 0.8 (D) 0.2 to 0.4

Last Answer : (C) 0.2 to 0.8

For turbulent flow in a tube, the heat transfer co-efficient is obtained from the Dittus-Boelter correlation. If the tube diameter is halved and the flow rate is doubled, then the heat transfer co-efficient will change by a factor of (A) 1 (B) 1.74 (C) 6.1 (D) 37

Description : For turbulent flow in a tube, the heat transfer co-efficient is obtained from the Dittus-Boelter correlation. If the tube diameter is halved and the flow rate is doubled, then the heat transfer co-efficient will change by a factor of (A) 1 (B) 1.74 (C) 6.1 (D) 37

Last Answer : (C) 6.1

Ideal refrigeration cycle is (A) Same as Carnot cycle (B) Same as reverse Carnot cycle (C) Dependent on the refrigerant's properties (D) The least efficient of all refrigeration processes

Description : Ideal refrigeration cycle is (A) Same as Carnot cycle (B) Same as reverse Carnot cycle (C) Dependent on the refrigerant's properties (D) The least efficient of all refrigeration processes

Last Answer : (B) Same as reverse Carnot cycle

Air-refrigeration cycle (A) Is the most efficient of all refrigeration cycles (B) Has very low efficiency (C) Requires relatively large quantities of air to achieve a significant amount of refrigeration (D) Both (B) and (C)

Description : Air-refrigeration cycle (A) Is the most efficient of all refrigeration cycles (B) Has very low efficiency (C) Requires relatively large quantities of air to achieve a significant amount of refrigeration (D) Both (B) and (C)

Last Answer : (D) Both (B) and (C)

The relative coefficient of performance is (a) actual COP/theoretical COP (b) theoretical COP/actual COP (c) actual COP x theoretical COP (d) 1-actual COP x theoretical COP

Description : The relative coefficient of performance is (a) actual COP/theoretical COP (b) theoretical COP/actual COP (c) actual COP x theoretical COP (d) 1-actual COP x theoretical COP

Last Answer : Ans: a

Full form of COP is A. Coefficient of Pressure B. Coefficient of performance C. Coefficient of program D. None of the above

Description : Full form of COP is A. Coefficient of Pressure B. Coefficient of performance C. Coefficient of program D. None of the above

Last Answer : Coefficient of performance

For proper refrigeration in a cabinet, if the temperature and vapour pressure difference between cabinet and atmosphereis 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

Description : For proper refrigeration in a cabinet, if the temperature and vapour pressure difference between cabinet and atmosphereis high, then (a) bigger cabinet should be used (b) smaller cabinet should ... tight vapour seal should be used (d) refrigerant with lower evaporation temperature should be used

Last Answer : Ans: c

If h1 = inner film co-efficient and /h2 = outer film co-efficient, then the overall heat transfer co-efficient is (A) Always less than h1 (B) Always between h1 and h2 (C) Always higher than h2 (D) Dependent on metal resistance

Description : If h1 = inner film co-efficient and /h2 = outer film co-efficient, then the overall heat transfer co-efficient is (A) Always less than h1 (B) Always between h1 and h2 (C) Always higher than h2 (D) Dependent on metal resistance

Last Answer : (B) Always between h1 and h2

Multipass heat exchangers are used (A) Because of simplicity of fabrication (B) For low heat load (C) To obtain higher heat transfer co-efficient and shorter tube (D) To reduce the pressure drop

Description : Multipass heat exchangers are used (A) Because of simplicity of fabrication (B) For low heat load (C) To obtain higher heat transfer co-efficient and shorter tube (D) To reduce the pressure drop

Last Answer : (C) To obtain higher heat transfer co-efficient and shorter tube

Controlling heat transfer film co-efficient is the one, which offers __________ resistance to heat transfer. (A) No (B) The least (C) The largest (D) Lower

Description : Controlling heat transfer film co-efficient is the one, which offers __________ resistance to heat transfer. (A) No (B) The least (C) The largest (D) Lower

Last Answer : (C) The largest

In an extended surface heat exchanger, fluid having lower co-efficient (A) Flows through the tube (B) Flows outside the tubes (C) Can flow either inside or outside the tubes (D) Should not be used as it gives very high pressure drop

Description : In an extended surface heat exchanger, fluid having lower co-efficient (A) Flows through the tube (B) Flows outside the tubes (C) Can flow either inside or outside the tubes (D) Should not be used as it gives very high pressure drop

Last Answer : (B) Flows outside the tubes

Indirect contact heat exchangers are preferred over direct contact heat exchangers, because (A) Heat transfer co-efficient are high (B) There is no risk of contamination (C) There is no mist formation (D) Cost of equipment is lower

Description : Indirect contact heat exchangers are preferred over direct contact heat exchangers, because (A) Heat transfer co-efficient are high (B) There is no risk of contamination (C) There is no mist formation (D) Cost of equipment is lower

Last Answer : (B) There is no risk of contamination