Air-refrigeration cycle________________?

Related Mcqs:

1. 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

2. 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

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. 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

5. Pure oxygen is mixed with air to produce an enriched air containing 50 volume % of oxygen. The ratio of moles of air to oxygen used is_________________?

   A. 1.72
   B. 0.58
   C. 0.5
   D. 0.2

6. A car tyre of volume 0.057 m3 is inflated to 300 kPa at 300 K. After the car is driven for 10 hours, the pressure in the tyre increases to 330 kPa. Assume air is an ideal gas and Cv for air is 21 J/mole.K. The change in the internal energy of air in the tyre in J/mole is__________________?

   A. 380
   B. 630
   C. 760
   D. 880

7. In case of vapour compression refrigeration system, elevating the evaporator temperature (keeping the condenser temperature constant) results in_____________?

   A. Enhanced COP
   B. Decreased COP
   C. No change in the value of COP
   D. Increased or decreased COP; depending upon the type of refrigerant

8. Fundamental principle of refrigeration is based on the ______________ law of thermodynamics?

   A. Zeroth
   B. First
   C. Second
   D. Third

9. Refrigeration capacity of a household refrigerator may be round about _____________ tons?

   A. 0.15
   B. 1.5
   C. 4.5
   D. 6.5

10. 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