Refrigeration And Air Conditioning Set 5

Mechanical Engineering

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This set of Refrigeration and Air conditioning Multiple Choice Questions & Answers (MCQs) focuses on Refrigeration And Air Conditioning Set 5

Q1 | Cryogenics
  • Is same as refrigeration
  • Include heating and cooling of liquids
  • Is a thermodynamic analysis of low temperature systems
  • Is the field of engineering associated with development, production and use of equipment in the range -180?C to absolute zero
  • None of the above
Answer: Is the field of engineering associated with development, production and use of equipment in the range -180?C to absolute zero
Q2 | Dew point is
  • The temperature at which ice starts melting in presence of air without external aid
  • Percentage of moisture contained in a sample of air
  • The temperature of water vapour in air starts
  • Partial pressure of water vapour in a sample of air
  • The temperature at which condensation of water vapour in air starts
Answer: The temperature at which condensation of water vapour in air starts
Q3 | A refrigerant with lowest freezing point temperature is
  • Ammonia
  • Freon 12
  • Freon 22
  • Carbondioxide
  • Freon 11
Answer: Freon 22
Q4 | A storage tank which receives liquid refrigerant from evaporator and prevents it from flowing into suction line is known as
  • Accumulator
  • Agitator
  • Balancer
  • Condenser
  • None of the above
Answer: Accumulator
Q5 | In a vapour compression refrigeration cycle using ammonia as a refrigerant the temperature of ammonia after compression will be at the range
  • 40?C to 0?C
  • 70?C to - 110?C
  • 0?C to - 15?C
  • ? 15?C to - 40?C
  • 50?C to 40?C
Answer: 70?C to - 110?C
Q6 | The condition of refrigerant before and after compression in vapour compression cycle is
  • Wet vapour, wet vapour
  • Dry saturated vapour, liquid
  • Dry saturated vapour, superheated vapour
  • Wet vapour, cry saturated vapour
  • Liquid, wet vapour
Answer: Wet vapour, cry saturated vapour
Q7 | The ratio of water vapour to the mass of dry air in a given mixture is known as
  • Humidity ratio
  • Relative humidity
  • Degree of saturation
  • Any of the above
  • None of the above
Answer: Humidity ratio
Q8 | When air is adiabatically saturated, the temperature attained is known as
  • Dew point temp
  • Dry bulb temp
  • Adiabatically sturated temp
  • Wet bulb temp
  • Critical temp
Answer: Wet bulb temp
Q9 | In case air is cooled by a process in which the humidity ratio of air does not change, the process is known as
  • Ventilation
  • Humidification
  • Chilling
  • Sensible cooling
  • Dehumidification
Answer: Sensible cooling
Q10 | If the compressor of a refrigeration system is noisy, it shows that
  • Compressor drive coupling is loose
  • Lack of oil
  • Internal parts of compressor broken
  • Compressor or motor loose on base
  • Any of the above
Answer: Any of the above
Q11 | Which of the following refrigerant is highly toxic?
  • Freon 12
  • Carbondioxide
  • Ammonia
  • Freon 22
  • Sulphurdioxide
Answer: Sulphurdioxide
Q12 | For for measurement of temperature in cryogenic range the thermometers used are
  • Gas thermometers
  • Electronic digital instruments
  • Mercury thermometers
  • Pyrometers
  • Radiation pyrometers
Answer: Gas thermometers
Q13 | The freezing point of ammonia is
  • ? 132.5?C
  • ? 20?C
  • ? 77.8?C
  • ? 202.5?C
  • 0?C
Answer: ? 77.8?C
Q14 | Presence of moisture in a refrigeration cycle will show its effect at
  • Compressor suction
  • Compressor discharge
  • Expansion valve
  • Condenser
  • All of the above
Answer: Expansion valve
Q15 | The colour of the flame of halide torch in case of leakage of freon refrigerant, will change to
  • Yellow
  • Violet
  • Green
  • Orange
  • Red
Answer: Green
Q16 | One tonne of refrigeration is equivalent to SI units of
  • 3.5 kW
  • 10 kW
  • 5 kW
  • 1 kW
  • 2.5 kW
Answer: 3.5 kW
Q17 | In vapour compression cycle the highest temperature of the refrigerant during the cycle occurs
  • After expansion valve
  • After evaporator
  • After condenser
  • After compression
  • None of the above
Answer: After compression
Q18 | Sub-cooling is
  • Removing sensible heat from a liquid
  • Removing latent heat from a gas
  • Cooling a liquid below 0?C.
  • Cooling a part of liquid
  • Differential cooling of a liquid
Answer: Cooling a part of liquid
Q19 | Which of the following refrigerant is the cheapest?
  • Air
  • Ammonia
  • Methyl chloride
  • Freon 12
  • Freon 22
Answer: Air
Q20 | Which of the following is not a property of Carbondioxide?
  • Non-toxic
  • Non-inflammable
  • Colourless
  • Pungent odour
  • All of the above
Answer: Pungent odour
Q21 | If a room has bad ammonia leaks
  • Lights should be switched off
  • No specific precautions are needed
  • One should wait for sometime
  • Gas mask should be put on
  • Before entering the room fans should be put on
Answer: Gas mask should be put on
Q22 | The moisture in a refrigeration system is removed by
  • Driers
  • Dehumidifiers
  • Evaporators
  • Coolers
  • None of the above
Answer: Driers
Q23 | When ammonia is used as a refrigerant in vapour compression cycle, the mass circulated per ton of refrigerating effect will be nearly
  • 0.2 kg
  • 1 kg
  • 1.2 kg
  • 0.5 kg
  • 1.8 kg
Answer: 0.2 kg
Q24 | Which type of compressor is commonly used in room air-conditioner
  • Reciprocating
  • Rotory
  • Screw
  • Centrifugal
  • None of the above
Answer: Reciprocating
Q25 | If the condensation temperature of a refrigerant is 25?C which type of condenser cannot be used?
  • Air cooled condenser
  • Water cooled condenser
  • Brine circulation condenser
  • Ice cooled condenser
  • Any of the above
Answer: Air cooled condenser
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