Refrigeration and Air Conditioning 6

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Subject: Refrigeration and Air Conditioning 6

Part 6: List for questions and answers of Refrigeration and Air Conditioning

Q1. Which refrigerant has the highest critical point temperature?
a) Ammonia
b) Freon 11
c) Freon 22
d) None of the above

Q2. The statement that molecular weight of all gases occupies the same volume at NTP is known as
a) Dalton’s law
b) Avogadro’s law
c) Joules law
d) Charles’s law

Q3. A Carnot refrigerator extracts 100 kcal of heat per minute from a cold room which is maintained at – 15 degree C and it is discharged to atmosphere 30 degree C the horse power required to run the unit would be
a) 1
b) 1.5 to 2
c) 5 to 6
d) More than 6

Q4. 2 HP per ton of refrigeration is required to maintain the temperature of – 40 degree C in the refrigerator if the refrigeration cycle works on Carnot cycle. The COP of the cycle would be
a) 1
b) 2.38
c) 4.76
d) 5

Q5. The effect of under cooling the refrigerant is to
a) Reducing the COP of the cycle
b) Increase the COP of the cycle
c) Reduce the refrigerating effect
d) None of the above

Q6. White ice is
a) Fast cooled water
b) Due to dissolved air, gases and impurities
c) Produced by blowing air during freezing
d) None of the above

Q7. Clear ice
a) Is pure ice
b) Contains dissolved gases
c) Is produced by blowing air during freezing
d) None of the above

Q8. Dry ice is
a) Free from water
b) Does not contain impurities
c) Solidified form of carbon dioxide
d) None of the above

Q9. A cooling tower in a refrigeration system
a) Removes heat from brine
b) Removes heat from lubricating oil
c) Removes heat from hot water coming out of condenser
d) None of the above

Q10. At 100% humidity
a) We bulb temperature is same as atmospheric temperature
b) Dry bulb temperature is same as atmospheric temperature
c) Wet bulb temperature is same as dry bulb temperature
d) Dry bulb temperature is exactly half the wet bulb temperature

Q11. The difference between wet and dry bulb temperature
a) Increases at atmospheric temperature
b) Increases as air gets drier
c) Remains constant always
d) None of the above

Q12. A low wet bulb temperature indicates
a) Very cool air
b) Very low humidity
c) (A) and (B) above
d) (a) and (c) above

Q13. A cooling tower cools water
a) Equal to wet bulb temperature
b) Slightly above wet bulb temperature
c) Wet bulb has no bearing on cooling load performance
d) None of the above

Q14. Capacity of a domestic refrigerator is in the range
a) 0.1 to 0.3 tonnes
b) 3 to 5 tonnes
c) 5 to 7 tonnes
d) 7 to 10 tonnes

Q15. The coefficient of performance of a domestic refrigerator as compared to that of an air conditioner is generally
a) More
b) Less
c) Air conditioner performance depends on whether conditions
d) Cannot be compared

Q16. The statement: If a maximum of gases or vapours is enclosed in a container, each will exert its own pressure on the container entirely independent of the others and the total absolute pressure will be equal to the sum of the partial pressure exerted by each of the gases. This statement is known as
a) Newton’s law of gases
b) Kinetic theory of gases
c) Flick’s law
d) Dalton’s law of partial pressures

Q17. One a psychometric chart cooling and humidification process using spray can be shown by
a) A horizontal line
b) A vertical line
c) A line parallel to dry bulb temperature lines
d) A line parallel to wet bulb temperature lines

Q18. Major modification required to produce temperature of – 200 deg C in a vapour compression refrigeration system using Freon 12 as refrigerant, is
a) Size of compressor required would be large to handle volumes of vapour
b) Compression ratio has to be restricted till stronger body of compressor is needed
c) Condenser capacity must be increased to handle the refrigerant
d) Freon 12 cannot be used for such low temperatures

Q19. Super-conductors
a) Offer no resistance to flow of heat at low temperatures
b) Offer no resistance to flow of electricity at low temperatures
c) Offer no resistance to flow of fluids at low temperatures
d) Can be rubbed with other superconductors without frictional effects at low
temperatures

Q20. Ten grams of moisture per kg of dry air is removed from atmospheric air during air conditioning and the temperature becomes 30 degree C. If the atmospheric conditions are 40 degree C DBT and 60% Relative humidity, the RH of air after refrigeration would be
a) 60%
b) 50%
c) 40%
d) 69%

Part 6: List for questions and answers of Refrigeration and Air Conditioning

Q1. Answer: b

Q2. Answer: b

Q3. Answer: b

Q4. Answer: b

Q5. Answer: b

Q6. Answer: b

Q7. Answer: c

Q8. Answer: c

Q9. Answer: c

Q10. Answer: c

Q11. Answer: b

Q12. Answer: d

Q13. Answer: b

Q14. Answer: a

Q15. Answer: b

Q16. Answer: d

Q17. Answer: d

Q18. Answer: d

Q19. Answer: b

Q20. Answer: d