The course of Refrigeration and Air Conditioning is of 2 years and where there is semester system, its complete study is done in 4 semesters or we can say that it is divided in 4 semesters, so below you are given the question paper of its 2nd semester which has been asked earlier in its exam, so solve it carefully and many more question papers related to this trade are given on our website, by solving which you can prepare yourself.
1. The refrigerant leaves the condenser as:
• High pressure saturated liquid
• Low pressure saturated liquid
• High pressure high temperature saturated liquid
• Low pressure high temperature saturated liquid
Answer:High pressure high temperature saturated liquid
2. The expansion valve used in central air conditioning plant should be:
• Capillary tube
• Thermostatic expansion valve
• Automatic expansion valve
• Down side float valve
Answer:Thermostatic expansion valve
3. The relation between rotor speed ‘N’, frequency ‘f’ and number of poles ‘P’ is expressed by an equation.
• N= 120f/p
• PN= 120/f
• f= 120N/P
• N = 120/f
Answer :N= 120f/p
4. High pressure cut out is used with…
• Condenser
• Evaporator
• Compressor
• Expansion valve
Answer :Compressor
5. Azeotropic refrigerant is:
• R4070
• R410A
• R717
• R502
Answer :R502
6. Under charging of the system is done by…
• COP increases
• COP decreases
• COP remains constant
• None of these
Answer:COP decreases
7. The alternative refrigerants of R11 are:
• R22
• R123
• R134a
• R125
Answer:R123
8. Dry compression can be avoided by installing…
• Liquid suction heat converter
• Accumulator
• Thermostatic expansion valve
• All these methods can be used
Answer:All these methods can be used
9. In case of three phase induction motor, slip is in the range of…
• 0.5% to 5%
• 2% to 10%
• 10% to 15%
• 15% to 20%
Answer:0.5% to 5%
10. Lubricating oils used with R134a:
• Mineral oil
• Poly ester
• Polyglycol
• None of these
Answer :Poly ester
11. The main drawback of HC refrigerants are their …..:
• High ODP
• High GWP
• Flammability
• High GWP and flammability
Answer :Flammability
12. The best suited compressor for large capacity and high volume flow rate is:
• Centrifugal
• Reciprocating
• Screw
• Scroll
Answer: Centrifugal
13. Domestic refrigeration works by:
• Vapour compression cycle
• Vapour absorption cycle
• Otto cycle
• None of these
Answer :Vapour compression cycle
14. High starting torque induction motors for compressors are used with ……..
• Capillary tube
• Condenser
• Float valve
• None of these
Answer :None of these
15. Liquid receiver is installed in ……
• Suction line
• Discharge line
• Liquid line
• Expansion line
Answer :Liquid line
16. HFC refrigerant is:
• R11
• R22
• R134a
• R290
Answer :R134a
17. Brine is a solution of…
• Ice and water
• Water and sodium chloride
• Water and acid
• None of these
Answer: Water and sodium chloride
18. The compressor of a car air conditioning system gets drive from…
• Solar panels
• Car batteries
• Car generators
• IC engine shaft
Answer: IC engine shaft
19. The dryer filters of a window AC are installed in…
• Suction line
• Discharge line
• Liquid line
• Expansion line
Answer: Liquid line
20. Refrigerant R 134a:
• Non-flammable
• Flammable
• Has low GWP
• Low ODP
Answer:Not flammable
21. The function of a condenser in a refrigeration system is to:
• Cool the surrounding air
• Cool the product or space
• Condense the excess vaporous refrigerant discharged by the compressor
• Condense the refrigerant entering the compressor
Answer:Condense the excess vaporous refrigerant discharged by the compressor
22. Screw compressors can be used for wet compression with refrigerants like…
• R134a
• R12
• NH3
• Water
Answer :NH3
23. The condenser of a car AC is:
• Water-cooled
• Air-cooled
• Evaporative type
• None of these
Answer :Air-cooled
24. The heat rejection capacity of the condenser should be:
• Equal to the cooling capacity
• More than the cooling capacity
• Less than the cooling capacity
• Equal to the compressor cooling capacity
Answer :More than the cooling capacity
25. A thermostatic expansion valve is used with…
• Window air-conditioners
• Split air-conditioners
• Central air-conditioning plant
• None of these
Answer: Central air-conditioning plant
26. It is a part of a vapour compression system:
• Absorber
• Pump
• Compressor
• Tube
Answer: Compressor
27. The capacity of a refrigeration plant is measured in…
• Litre
• Metric ton
• TR
• Kilogram
Answer: TR
28. The length and diameter of a capillary tube are:
• Small
• Large
• Small and large respectively
• Long and short
Answer: Long and short
29. In a condenser, the refrigerant first loses its:
• latent heat
• sensible heat
• Sometimes sensible and sometimes latent heat
• None of these
Answer: sensible heat
30. The following alternative refrigerants used in car air-conditioning systems are:
• R1234yf
• R1234ze
• R764
• None of these
Answer:R1234yf
31. Temporary fastening done by:
• Welding
• Brazing
• Soldering
• Rivets
Answer:Rivets
32. Pressure testing of the following equipment in the plant is not required:
• Compressors
• Evaporators
• Condensers
• None of these
Answer:Compressors
33. The indoor unit in a split AC consists of?
• Evaporator and blower
• Evaporator coil, blower and capillary tube
• Evaporator coil, blower and motor, air filter, control panel, supply and return air grills
• Evaporator coil, air filter, control panel, supply and return air grills, capillary tube
Answer:Evaporator coil, blower and motor, air filter, control panel, supply and return air grills
34. Window ACs can be easily converted from cooling to heating mode by installing a…
• Two way reverse valve
• Four way reverse valve
• Throttle valve
• Three way reverse valve
Answer:Four way reverse valve
35. The enthalpy in a capillary tube during expansion:
• Increases
• Decreases
• No change
• None of these
Answer: No change
36. The efficiency of a water cooled condenser is:
• Less than an air cooled condenser
• Same as an air cooled condenser
• More than an air cooled condenser
• None of these
Answer: More than an air cooled condenser
37. The main components of a centrifugal compressor are :
• ‘Eye’
• Impeller
• Diffuser
• Both (a) and (b)
Answer :Both (a) and (b)
38. The power consumption of a 1TR window AC falls in the range of …….
• 1 to 1.5kw
• 1.5 to 2kw
• 2kw to 2.5kW
• 3 to 3.5kw a.
Answer :2kw to 2.5kW
39. The dryer in a refrigeration system has the ability to :
• Separate the lubricant from the refrigerant
• Remove moisture from the refrigerant
• Maintain the level of liquid refrigerant in the system
• Aid in dry compression of the refrigerant
Answer :Remove moisture from the refrigerant
40. PUF stands for:
• Polyusar Foam
• Polyurea Foam
• Polyurethane Foam
• Polyurea Urethane Foam
Answer:Polyurethane Foam
41. Pipeline pressure drops more in split AC than in window AC because of:
• Long distance of suction and discharge lines
• Two units i.e. inner and outer unit
• Long distance of discharge and liquid lines
• Long distance of suction and liquid lines
Answer:Long distance of suction and liquid lines
42. HCFC refrigerants are:
• R12
• R22
• R134a
• R600
Answer:R22
43. In a hermetically sealed compressor, the compressor motor is cooled by…
• Water
• Air
• Refrigerant
• Nitrogen
Answer:Air
44. Disadvantages of automatic expansion valve are:
• Mass flow rate increases as load increases
• Mass flow rate decreases as load increases
• Not suitable for different loads
• Both (a) and (c)
Answer:Both (a) and (c)
45. Standing vacuum test indicates low vacuum after 24 hours.
• Presence of moisture
• Leak in the system
• Both (a) and (b)
• None of these
Answer:Both (a) and (b)
46. Hissing or gurgling sound is produced at the exhaust of…….
• Evaporator
• Compressor
• Capillary tube
• Condenser
Answer:Capillary tube
47. The thickness of the fins used on the condenser coil of a window AC is approximately?
• 0.5 cm
• 0.2 mm
• 0.2 cm
• 0.5 mm
Answer:0.2 mm
48. Overheating in the evaporator is caused by……?
• Increase in capacity
• Increase in compressor power consumption
• Increase in COP only
• Both (a) and (b)
Answer: Increase in compressor power consumption
49. In a vapour compression refrigeration system with liquid refrigerant the lowest temperature occurs after …..?
• Compression
• Condensation
• Evaporation
• Expansion
Answer :Expansion
50. HFC refrigerant has:
• Low ODP value
• High ODP value
• Low GWP
• Zero ODP
Answer: Zero ODP
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