Refrigeration And Air Conditioning Set 8

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This set of Refrigeration and Air conditioning Multiple Choice Questions & Answers (MCQs) focuses on Refrigeration And Air Conditioning Set 8

Q1 | In order to ensure leak proof mechanical links, the end of copper tubing in refrigeration cycle is
  • Flared
  • Brazed
  • Soldered
  • Press-fitted
  • (C) and (D) together
Q2 | A Bell-Coleman cycle is
  • Reversed Otto cycle
  • Reversed Carnot cycle
  • Reversed Sterling cycle
  • Reversed Joule cycle
  • Reversed Rankine cycle
Q3 | On a particular time of a day if dry bulb temperature is equal to the wet bulb temperature, then it can be safely concluded that
  • Dew point was less than 20?C
  • Rain had occurred one or two hours earlier
  • Relative humidity of air was 100%
  • Specific humidity of air was 0.010 kg per kg of dry air
  • Atmospheric air was free from moisture
Q4 | Which of the following is not a dehydrator?
  • Silica sel
  • Molecular sieve
  • Calcium chloride
  • Sodium chloride
  • All of the above
Q5 | A water cooler is installed with one ton vapour compression cycle. In 24 hours it will provide
  • 0.1 ton of cold water
  • One tonne of cold water
  • The change is gradual throughout the cycle
  • More than one tonne of cold water
  • Half ton of cold water
Q6 | In rainy season desert coolers become ineffective
  • Because of low temperature
  • Pleasant weather
  • Rain serves the purpose of cooler
  • Humidity of air increases
  • None of the above
Q7 | When Freon 12 is the refrigerant, the condenser and evaporator cables are made of
  • Aluminium
  • Cast iron
  • Steel
  • Copper
  • Wrought iron
Q8 | In vapour absorption system using ammonia, water is required for
  • Absorber only
  • Separator only
  • Condenser, absorber and separator
  • Condenser only
  • Condenser and absorber
Q9 | The ratio of mass of water vapour associated with unit mass of dry air to the mass of water vapour associated with unit mass of dry air saturated at the same temperature is known as
  • Relative humidity
  • Specific humidity decreases
  • Humidity ratio
  • Degree of saturation
  • None of the above
Q10 | In a refrigerator system if compressor fails to operate, the probable reason could be
  • Power failure
  • Low voltage
  • Burnt motor
  • Fuse blown
  • Any of the above
Q11 | A thermometer in vapour compression system is installed in the main line close to the compressor
  • As it helps the operator to adjust compressor for greatest efficiency
  • As temperature indicates whether liquid or vapour refrigerant is going to compressor
  • As temperature helps in calculating the coefficient of performance
  • As the performance of other units of the cycle can be controlled
  • None of the above
Q12 | White ice is
  • Sub-cooled water
  • Fast cooled water
  • Due to dissolved air, gases and impurities
  • Produced by blowing air during freezing
  • None of the above
Q13 | In which type of single phase motor the starting torque is low
  • Capacitor start type
  • Shaded pole type
  • Starting torque is same in all motors
  • Permanent split capacitor type
  • Capacitor start and capacitor run type
Q14 | Air conditioning means
  • All above
  • Removal of air impurities
  • Heating
  • Dehumidifying
  • Cooling
Q15 | Dew points temperature is an indication of
  • Moisture content of air
  • Dryness of air
  • Lowest temperature where air and water vapour start separating
  • Condition air
  • Any of the above
Q16 | The most common type of vapour absorption system in use for industrial application is
  • Hydrogen and water
  • Freon 22 and water
  • Brine and water
  • Freon 12 and water
  • Ammonia and water
Q17 | Brazing is the process used for joining
  • Two ferrous materials
  • One ferrous and one non-ferrous material
  • Two non-ferrous materials
  • Two non-metals
  • None of the above
Q18 | Of the following chemicals the liquid having the greatest cooling effect on an individual is
  • Water
  • Water containing ammonium hydroxide
  • Ether
  • Alcohol
  • Brine
Q19 | In vapour absorption system the function of rectifier is
  • To cool the vapour leaving the analyzer
  • To separate ammonia and water
  • To dissolve ammonia in water
  • To add energy from external source
  • None of the above
Q20 | Sometimes refrigeration plants use cooling towers. The water cooled in those towers is supplied
  • For defrosting evaporator coils
  • To cool compressor cylinder only
  • To cool refrigerant in evaporator
  • To cool refrigerant in condenser
  • None of the above
Q21 | When moisture is added to air at constant dry bulb temperature, the process is known as
  • Humidification
  • Sensible cooling
  • Wetting
  • Chilling
  • None of the above
Q22 | The condition of refrigerant before and after the condenser in a vapour compression cycle is
  • Wet vapour, wet vapour
  • Dry saturated, wet vapour
  • Dry saturated, dry saturated
  • Liquid, liquid
  • Dry saturated, saturated liquid
Q23 | The COP of a reversed Carnot cycle is 5. The ratio of highest absolute temperature to the lowest absolute temperature
  • 0.8
  • 1.2
  • 0.2
  • 1.25
  • 5
Q24 | In case the relative humidity of atmospheric air is 100% the rate of evaporation of water will be
  • Half the water already air
  • Very high
  • Zero
  • Slow
  • Half the water already air
Q25 | In which of the following plants secondary refrigerant is used?
  • Domestic refrigerator
  • Room air conditioner
  • Deep freezer
  • Ice plant
  • None of the above