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 3rd 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 advantages of screw compressor are:
•High pressure refrigerants can be used with it
•Its speed is as high as that of a centrifugal compressor
•Both (a) and (b)
•None of the above
Answer: Both (a) and (b)
2. The low side float valve maintains the refrigerant level in the…….
•Condenser
•Evaporator
•Clogged evaporator
•None of these
Answer: Evaporator
3. The efficiency of a cooling tower is the ratio of ……….
•Range of difference between the temperature of water leaving the cooling tower and the temperature of water entering the cooling tower
•Approach to the difference between the temperature of water leaving the cooling tower and the temperature of water entering the cooling tower
•Range of difference between the wet bulb temperature of ambient air and the temperature of water leaving the cooling tower
•None of the above
Answer: Range of difference between the wet bulb temperature of ambient air and the temperature of water leaving the cooling tower
4. Refrigeration plants are charged by providing refrigerants from cylinders at ………
•Expansion valve
•Receiver
•Suction of compressor
•Evaporator
Answer :Suction of compressor
5. Condenser pressure between water cooled condenser and air cooled condenser (operating in unsaturated air) for the same capacity of refrigerant plant:
•Will be higher in water cooled condenser than air cooled condenser
•Will be same in both the condensers
•Will be higher in air cooled condenser than water cooled condenser
•Does not depend on the cooling medium
Answer: Will be higher in air cooled condenser than water cooled condenser
6. In centrifugal compressors:
•Impeller has vanes whereas diffusers are without vanes
•Diffusers have vanes whereas impellers are without vanes
•Both diffuser and impeller have vanes
•Both diffuser and impeller are without vanes
Answer:Impeller has vanes whereas diffusers are without vanes
7. The accessibility of a cooling tower is defined as follows:
•Difference between the dry bulb temperature of the ambient air and the temperature of water leaving the cooling tower
•Difference between the wet bulb temperature of the ambient air and the temperature of water leaving the cooling tower
•Difference between the temperature of water leaving the cooling tower and the temperature of water entering the cooling tower
•None of the above
Answer:Difference between the wet bulb temperature of the ambient air and the temperature of water leaving the cooling tower
8. Volumetric efficiency depends on:
•Pressure ratio
•Clearance ratio
•Index of compression
•All of the above
Answer:All of the above
9. Piping of ……. is used in cold storage plants.
•Copper
•Bronze
•Steel
•Brass
Answer:Steel
10. In shell and tube type condenser :
•Water flows normally through the shell
•Water flows normally through the tube
•Both water and refrigerant first mix, cool and separate
•None of these
Answer: Water flows normally through the tube
11. The heat rejection ratio of a condenser is defined as which of the following?
•The cooling effect produced in the evaporator is reduced by the heat rejected in the condenser -+
•1 + (heat rejected in the condenser/cooling effect)
•heat rejected in the condenser/cooling effect in the evaporator
•None of these
Answer:heat rejected in the condenser/cooling effect in the evaporator
12. Centrifugal A.C. plant uses which of the following extension devices?
•Automatic expansion valve
•Thermostatic expansion valve
•Capillary tube
•High side float valve
Answer: Thermostatic expansion valve
13. Reciprocating compressors are not suitable for refrigeration plants having capacity more than 100 TR due to……..
•High pressure
•High volume flow rate
•Both (a) and (b)
•None of these
Answer: Both (a) and (b)
14. The range of a cooling tower is defined as follows :
•The difference between the temperature of water entering the cooling tower and the temperature of water leaving the cooling tower in the range.
•The difference between the temperature of water entering the cooling tower and the temperature of water leaving the cooling tower in the approach.
•The difference between the temperature of water entering the cooling tower and the wet bulb temperature of the air in the range.
•None of the above
Answer:The difference between the temperature of water entering the cooling tower and the wet bulb temperature of the air in the range.
15. ……… refrigerant is used in water cooler.
•R12
•R21
•R134a
•R717
Answer :R134a
16. The purpose of a cooling tower is:
•Cooling the air coming from the condenser
•Cooling the hot water coming from the condenser
•Cooling the air coming from the condenser through water
•None of the above
Answer: Cooling the hot water coming from the condenser
17. Clearance ratio is defined as the following ratio:
•Clearance volume to stroke volume
•Stroke volume to clearance volume
•Clearance volume to total volume
•Stroke volume to total volume
Answer :Clearance volume to stroke volume
18. In case of ……….. an oil separator is necessary to transmit the oil in the discharge line back to the compressor. —
•R290
•Ammonia
•R12
•R600a
Answer :Ammonia
19. External equalizer is used with…………?
•Automatic expansion valve
•Thermostatic expansion valve
•Capillary tube
•High side float valve
Answer: Thermostatic expansion valve
20. The most commonly used insulating material in cold storage is:
•PUF
•Thermocol
•Cork
•Glass Wool
Answer :PUF
21. In the hot gas bypass method of compressor capacitance control, the hot compressed gas :
•It is transmitted to the liquid line
•It is transmitted to the discharge line
•It is transmitted to the suction line
•It is transmitted to the expansion line
Answer:It is transmitted to the suction line
22. Evaporative condenser is:
•Air cooled condenser
•Water cooled condenser
•Both air cooled and water cooled at the same time
•None of these
Answer:Both air cooled and water cooled at the same time
23. Increasing volumetric efficiency due to increase in pressure ratio :
•It increases
•It decreases
•Changing the pressure ratio does not change the volumetric efficiency
•It may increase or decrease, it also depends on other factors
Answer: It decreases
24. Evaporator converts low pressure low temperature liquid refrigerant into………….
•High pressure liquid refrigerants
•Low pressure liquid and vapor refrigerants
•Low pressure vapor refrigerants
•None of the above
Answer: Low pressure vapor refrigerants
25. Scale formation in a condenser is due to which of the following?
•Increase in heat transfer
•Decrease in heat transfer
•Increase in condenser pressure
•Both (b) and (c)
Answer: Both (b) and (c)
26. The refrigerant used in deep freezers these days is
•HCFC
•CFC
•HFC
•HC
Answer :HFC
27. A dry evaporator is one in which :
•Dry saturated refrigerant is issued from the evaporator
•Superheated refrigerant is issued from the evaporator
•Refrigerant with high dryness fraction is issued from the evaporator
•There is refrigerant with some dryness fraction at the inlet of the evaporator
Answer: There is refrigerant with some dryness fraction at the inlet of the evaporator
28. Reasons for suction line liquid line heat exchanger :
•Substantial cooling of the liquid refrigerant entering the expansion device
•Superheating of the suction vapour occurs
•COP may increase or decrease
•All of the above
Answer:All of the above
29. Where is secondary refrigerant used stationary?
•In domestic refrigerators
•In ice plants
•In deep freezers
•In water coolers
Answer: In ice plants
30. In water cooled condenser systems, pressure relief valves are installed at ………
•Compressor
•Receiver
•Condenser
•None of these
Answer: Receiver
31. The following are the disadvantages of refrigerants which are completely miscible with mineral oils used in compressors:
•These reduce the system efficiency
•Reduce compressor power
•Increase heat transfer
•None of these
Answer:These reduce the system efficiency
32. Walk in coolers are refrigeration systems having area range of :
•2 sq. feet to 5 sq. feet
•5-10 sq. feet
•10-30 sq. feet
•30 sq. feet to 10000 sq. feet
Answer :30 sq. feet to 10000 sq. feet
33. Which of the following is a method of food processing :
•Dehydration
•Hydration
•Canning
•Both (a) and (c)
Answer: Both (a) and (c)
34. The freezing point of chocolate is :
•20°C
•25°C
•30°C
•35°C
Answer :25°C
35. The main function of the compressor is:
•Increasing the pressure of the refrigerant
•Increasing the temperature of the refrigerant
•Increasing both the pressure and temperature of the refrigerant
•Superheating the refrigerant
Answer: Increasing both the pressure and temperature of the refrigerant
36. The temperature range in a visible cooler is:
•-5 to 0°C
•2 to 8°C
•8 to 12°C
•None of these
Answer: 2 to 8°C
37. The storage temperature of milk is :
•12°C
•-10°C
•2°C
•5°C
Answer :2°C
38. In scroll compressors :
•Both the discharge port and the suction port are located on the outer circumference. •
Both the discharge port and the suction port are located near the centre.
•The suction port is located in the centre and the discharge port is located on the outer circumference.
•The discharge port is located in the centre and the suction port is located on the outer circumference.
Answer :The discharge port is located in the centre and the suction port is located on the outer circumference.
39. Open type reciprocating compressor motor is cooled by……….
•Refrigerant entering the compressor
•Air
•Water
•Liquid sodium metal
Answer: Air
40. In an air cooled condenser the condensing temperature is maintained within the required limits by which of the following?
•By changing the quantity of air through the condenser
•By changing the temperature of the ambient air
•By changing both the quantity and temperature of the ambient air
•None of these
Answer: By changing both the quantity and temperature of the ambient air
41. Suction line liquid line heat exchangers are desired in low capacity refrigeration systems because:
•It increases the COP
•It does not cause eye compression
•It reduces the brightness at the time of entry into the evaporator
•None of these
Answer:It reduces the brightness at the time of entry into the evaporator
42. Domestic refrigerators work on the principle of…………?
•Vapor Compression Cycle
•Vapor Observation Cycle
•Diesel Cycle
•None of these
Answer:Vapor Compression Cycle
43. Freeze drying is……process?
•Separation of liquid from a single phase product
•Occurs in vacuum
•Sublimation of liquid
•All of the above
Answer: All of the above
44. Brine is an aqueous solution of water and ………..
•Magnesium sulphate
•Sodium chloride
•Calcium carbonate
•None of these
Answer: Sodium chloride
45. The volumetric efficiency of a compressor is defined as the ratio of…………
•Actual magnitude of piston displacement from
•Actual magnitude of piston displacement from
•Pressure before compression from pressure after compression
•Pressure after compression from pressure before compression
Answer:Actual magnitude of piston displacement from
46. Thermostatic expansion valve is based on the principle of maintaining a constant degree of superheating at…….
•Discharge of compressor
•Output of condenser
•Output of capillary tube
•Output of evaporator
Answer :Output of evaporator
47. Direct expansion coil evaporator is:
•Flooded type evaporator
•Fry type evaporator
•Wet type evaporator
•None of these
Answer: Fry type evaporator
48. Capillary tube is used between……..
•Compressor and condenser
•Evaporator and compressor
•Evaporator and condenser
•None of these
Answer: Evaporator and condenser
49. High pressure cut off is used for:
•To cut off the supply to the condenser fan motor if the pressure increases beyond the predetermined limit.
•To cut off the supply to the compressor motor if the pressure increases beyond the predetermined limit.
•To cut off the supply to the evaporator fan motor if the pressure increases beyond the predetermined limit.
•None of the above
Answer:To cut off the supply to the compressor motor if the pressure increases beyond the predetermined limit.
50. In forced draft cooling tower, fan is installed in ……….
•At the top of the cooling tower
•In the middle of the cooling tower
•At the bottom of the cooling tower
•Anywhere in the cooling tower
Answer: At the bottom of the cooling towerIn this post very important information has been given related to refrigeration and air conditioning previous question papers jntuk refrigeration and air conditioning questions and answers pdf in Hindi iti rac question paper in Hindi iti mrac trade question paper. If you find this information useful then share it with your friends and if you want to know or ask something about it then definitely ask by commenting below.