Refrigeration and Air Conditioning 4

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Mechanical Engineering MCQ Question Papers: DRDO, ISRO, Interview

Subject: Refrigeration and Air Conditioning 4

Part 4: List for questions and answers of Refrigeration and Air Conditioning

Q1. If a room has bad ammonia leaks
a) Before entering the room fans should be put on
b) Lights should be switched off
c) Gas mask should be put on
d) No specific precautions are needed

Q2. Freon type (halocarbons) refrigerants are
a) Poisonous
b) Non-poisonous
c) Coloured
d) Have peculiar odour

Q3. Cryogenics
a) Is same as refrigeration
b) Include heating and cooling of liquids
c) Is the field of engineering associated with development, production and use of
equipment in the range -180?C to absolute zero
d) None of the above

Q4. The change in temperature resulting from a gas expanding from one constant pressure, with no heat transfer and no external work other than to maintain the constant pressure is known as
a) Dalton’s law of partial pressures
b) Law of conservation of energy
c) Avogadro’s hypothesis
d) Joule – Thomoson effect

Q5. An average adult while sitting in a cinema hall
a) Absorbs about 100 kcal of heat per hour
b) Discards about 500 kcal of heat per hour
c) Discharges about 100 kcal of heat per hour
d) Neither absorbs nor discards heat

Q6. While designing air conditioning system for a theatre the various heat loads are categorized as given below. Which one will give lowest heat load?
a) Direct sun
b) Human beings
c) Lights
d) Outside temperature in summer

Q7.In psychometric chart vertical lines indicate
a) Dry bulb temperature
b) Wet bulb temperature
c) Percentage humidity
d) Relative humidity

Q8. In a psychometric chart horizontal line indicate
a) Dry bulb temperature
b) Dew point temperature
c) Percentage humidity
d) Relative humidity

Q9. For better performance a desert cooler
a) Should be placed inside the room
b) Should be mounted on window
c) Should be placed at the roof level
d) None of the above

Q10. In rainy season desert coolers become ineffective
a) Because of low temperature
b) Pleasant weather
c) Humidity of air increases
d) None of the above

Q11. In central air conditioning system
a) Entire equipment is placed in the air conditioned space
b) There is only one machine which performs the function of air conditioning
c) All the major equipment is located in one central space removed from the air to be conditioned
d) None of the above

Q12. In control cooling water system, chromates, phosphates and silicates are added to water
a) To prevent scale formation
b) To remove odour
c) To inhibit corrosion
d) To prevent algae growth

Q13. Ph value of a brine solution is
a) 70
b) Less than 7
c) 14
d) Could be any value

Q14. Air conditioning means
a) Cooling
b) Dehumidifying
c) Removal of air impurities
d) All above

Q15. The crankcase explosion of a refrigeration compressor
a) Means breakdown in compression
b) Occurs when load is too high
c) Means ignition of refrigeration due to high temperature
d) Occurs due to ignition of vapours in compressor crank case

Q16. During adiabatic saturation process on unsaturated air
a) Dry bulb temperature remains constant
b) Wet bulb temperature remains constant
c) Dew point temperature remains constant
d) None of the above

Q17. On a psychometric chart sensible heating or cooling is represented by
a) A horizontal line
b) A vertical line
c) Curved line
d) None of the above

Q18. If wet bulb temperature is same as dew point, the relative humidity of air will be
a) 0
b) 25
c) 67
d) 100

Q19. Dew point is
a) Percentage of moisture contained in a sample of air
b) Partial pressure of water vapour in a sample of air
c) The temperature at which condensation of water vapour in air starts
d) The temperature at which ice starts melting in presence of air without external aid

Q20. In case of completely dry air
a) Total heat is same as latent heat
b) Total heat is same as sensible heat
c) Total heat is sum of sensible heat and latent heat
d) Total heat is sum of sensible heat required for all individual constituents

Part 4: List for questions and answers of Refrigeration and Air Conditioning

Q1. Answer: c

Q2. Answer: b

Q3. Answer: c

Q4. Answer: d

Q5. Answer: c

Q6. Answer: c

Q7. Answer: a

Q8. Answer: b

Q9. Answer: b

Q10. Answer: c

Q11. Answer: c

Q12. Answer: c

Q13. Answer: d

Q14. Answer: d

Q15. Answer: d

Q16. Answer: b

Q17. Answer: a

Q18. Answer: d

Q19. Answer: c

Q20. Answer: b