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?

Related Mcqs:

1. A refrigeration cycle is a reversed heat engine. Which of the following has the maximum value of the co-efficient of performance (COP) for a given refrigeration effect ?

   A. Vapor compression cycle using expansion valve
   B. Air refrigeration cycle
   C. Vapor compression cycle using expansion engine
   D. Carnot refrigeration cycle

2. 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

3. 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

4. Pressure-enthalpy chart is useful in refrigeration. The change in internal energy of an ideal fluid used in ideal refrigeration cycle is_____________________?

   A. Positive
   B. Negative
   C. Zero
   D. Infinity

5. 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

6. 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

7. 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

8. 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

9. 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

10. 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