Refrigeration and Air Conditioning 5

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Mechanical Engineering MCQ Question Papers: DRDO, ISRO, Interview

Subject: Refrigeration and Air Conditioning 5

Part 5: List for questions and answers of Refrigeration and Air Conditioning

Q1. For measurement of temperature in cryogenic range the thermometers used are
a) Pyrometers
b) Radiation pyrometers
c) Gas thermometers
d) Electronic digital instruments

Q2. Dischloromono fluoroethane is
a) Freon 11
b) Freon 12
c) Freon 22
d) None of the above

Q3. A Salinometer
a) Measures temperatures in cryogenic regions
b) Measure intensity of illumination
c) Measures density of brine
d) Measures solar radiation

Q4. Dew points temperature is an indication of
a) Moisture content of air
b) Dryness of air
c) Lowest temperature where air and water vapour start separating
d) Any of the above

Q5. During dehumidification process
a) Specific humidity increases
b) Specific humidity decreases
c) Relative humidity decreases
d) Relative humidity does not change

Q6. Under increased atmospheric pressure (as compared to the standard conditions) the steam will condense at
a) More than 100 deg C
b) Less than 100 deg C
c) Has nothing to do with pressure
d) Depends on other conditions

Q7. Dalton’s law of partial pressure state that
a) All gases exert partial pressures only
b) All gases or mixture of gases in a container will exert their own pressure on the
container entirely independent of the others
c) Total pressure exerted by a mixture of gases or vapours is equal to the pressure
exerted by individual gases or vapours
d) None of the above

Q8. Dehydration means
a) Removing hydrogen from a mixture
b) Removing hydrogen from a hydrocarbon
c) Removing steam from any matter
d) Removing water from any matter

Q9. Anhydrous substance is
a) Free of hydrogen
b) Free of hydrogen and other chemicals containing hydrogen
c) Free of water especially water of crystallization
d) Dry substance

Q10. Dehumidification means
a) Removing humidity from a space
b) Reducing the quantity of water vapour in a space
c) Reducing the moisture content of a substance
d) Any of the above

Q11. The type of compressor used in refrigeration system is
a) Reciprocating
b) Centrifugal
c) Rotary screw compressor
d) All of the above

Q12. A hermetic compressor is
a) A reciprocating compressor
b) A thermodynamically efficient compressor
c) A factory sealed unit containing motor and compressor
d) None of the above

Q13. In a refrigeration system a condenser
a) Receives liquid refrigerant and supplies liquid refrigerant
b) Receives vapour refrigerant and supplies liquid refrigerant
c) Receives liquid refrigerant and supplies liquid refrigerant
d) None of the above

Q14. The function of de superheating coil in a condenser is
a) To remove heat from condenser
b) To discharge the heat exchanged in condenser to the surroundings
c) To remove the heat of superheat of the refrigerant before it enters the condenser
d) None of the above

Q15. In a refrigerator evaporator is located
a) On the bottom of refrigerator cabinet
b) Adjacent to compressor
c) Inside the refrigerator cabinet
d) On the side of condenser

Q16. If a refrigerator compressor cuts out on starter overloads the probable reason could be
a) Low line voltage
b) Suction pressure high
c) Compressor tight
d) Any of the above

Q17. A thermometer in vapour compression system is installed in the main line close to the compressor
a) As it helps the operator to adjust compressor for greatest efficiency
b) As temperature helps in calculating the coefficient of performance
c) As the performance of other units of the cycle can be controlled
d) None of the above

Q18. A thermometer in the compressor discharge line
a) Confirms the flow of refrigerant
b) Indicates the efficiency of cycle
c) Shows the heat of refrigerant leaving the cylinder on way to the condenser
d) None of the above

Q19. A pressure gauge on the discharge side of compressor
a) Indicates the temperature of refrigerant after compression
b) Gives a warning when the pressure reaches a dangerous point
c) Confirms the flow of refrigerant in cycle
d) Is mounted for show only

Q20. Out of the following refrigerants which one will provide highest compressor
displacement per tonne of refrigeration in a vapour compression system operating between fixed temperatures
a) Ammonia
b) Freon 11
c) Freon 22
d) Carbon dioxide

Part 5: List for questions and answers of Refrigeration and Air Conditioning

Q1. Answer: c

Q2. Answer: c

Q3. Answer: c

Q4. Answer: a

Q5. Answer: c

Q6. Answer: a

Q7. Answer: b

Q8. Answer: d

Q9. Answer: c

Q10. Answer: c

Q11. Answer: d

Q12. Answer: c

Q13. Answer: b

Q14. Answer: c

Q15. Answer: c

Q16. Answer: d

Q17. Answer: a

Q18. Answer: c

Q19. Answer: b

Q20. Answer: b