Refrigeration And Air Conditioning Previous Question papers : For all the candidates preparing for the ITI RAC exam, we keep providing important information related to it on our website from time to time. If you are preparing for ITI RAC, then you can improve your preparation by using the mock test, online free test and practice set given on our website. In today’s post, we are giving some important questions asked in the ITI RAC exam and their answers, which you should remember carefully because these have been asked in previous exams and these can be asked in upcoming exams as well.
ITI Electronic Mechanic 4th Semester Exam Papers
Refrigeration And Air Conditioning Previous Question papers
1. How do large campuses with many buildings handle their cooling systems?
• Each building has its own conditioning unit
• Each building has window units on every floor
• There is an extensive central air conditioning system campus-wide
• Any of the above
Answer. There is an extensive central air conditioning system campus-wide
2. Which of the following is a key component that moves refrigerant through a central AC?
• Condensing coil
• Expansion valve
• Evaporator
• Compressor
Answer. Compressor
3. What type of material would you use to clean a condenser coil?
• Soap and water
• Commercial coil cleaner
• Bleach and mineral water
• Any of the above
Answer. Commercial Coil Cleaner
4. What should you use to prevent mold growth in your central air conditioner?
• Ammonia
• Bleach
• Vinegar
• None of the above
Answer. Bleach
5. Cleaning condenser fins with a hose is a bad idea because of what?
• Water will turn dust into sludge, making it harder to clean
• Use water. It’s a bad idea – No
• Water will cause the fins to rust faster
• None of the above
Answer. Water will turn dust into sludge, making it harder to clean
6. An air conditioner…
• Humidifies
• Stabilizes
• Stymizes
• Dehumidifies
Answer. Dehumidifies
7. Why are some air conditioning units called split units?
• Some parts of the unit are installed outside and some inside the house
• Parts of the unit are installed on different floors of the house
• The unit is interchangeable with other appliances in the house
• None of the above
Answer. Some parts of the unit are installed outside and some inside the house
8. What is the main mechanical difference between a window and a large split AC?
• Different types of coolants are used in them
• Different types of refrigerants are used in them
• Different types of thermometers are used in them
• There is no difference between them
Answer. There is no difference between them
9. Which part of an air conditioning unit helps us in cleaning the air?
• Filter
• Air compressor
• Air handler
• Evaporator
Answer. Filters
10. Package air conditioners are usually of ……. capacity.
• 3-5 tons
• 15 tons
• 7-10 tons
• All of these
Answer. All of these
11. Compressor in a package unit………
• Pumps refrigerant throughout the system
• Converts gaseous refrigerant to liquid refrigerant
• Converts liquid refrigerant to gaseous refrigerant
• Removes heat from the refrigerant
Answer. Pumps refrigerant throughout the system
12. Dryer in a packaged unit………
• Helps in starting the condenser fan
• Removes humidity from the air
• Removes moisture and debris from the refrigerant
• Removes moisture from the condenser pan
Answer. Removes moisture and debris from the refrigerant
13. Air conditioning is required……… in the manufacturing of precision parts.
• To achieve close tolerance
• To prevent corrosion
• To provide clean environment
• All of these
Answer. To achieve close tolerance
14. Modern electronic equipment require cooling because of ……….
• Dissipation of relatively large amount of heat in a small space
• Prevention of aggressive activity
• Improvement in longevity
• All of these
Answer. All of these
15. In small residential spaces and offices ………. are used.
• Window or split air conditioners
• Window air conditioners or central air conditioning
• Split air conditioners or central air conditioning
• Window or split AC or central air conditioning
Answer. Window or split air conditioners
16. In a vapour absorption system, the refrigerant is absorbed by the absorbent through ……….
• Absorption of heat
• Not due to thermal effect
• Release of heat
• Reduction in volume
Answer. Release of heat
17. The function of air diffuser in air conditioning is to…
• Clean the air
• To flow air in a desired manner
• To reduce the noise of the air conditioner
• To control the relative humidity of the air
Answer. To flow air in a desired manner
18. Cold storage can be used to store…
• Live products like fruits and vegetables only
• Both live and dead products
• Dead products like meat, fish only
• None of these
Answer. Both live and dead products
19. Rapid freezing of products is done for…
• Decrease in cell damage due to ice crystal growth
• Decrease in energy consumed in refrigeration systems
• Decrease in bacterial contamination
• All of these
Answer. Reduction in cell damage due to ice crystal growth
20. Air conditioning involves ……….
• Controlling temperature
• Controlling humidity
• Controlling air speed and air purity
• All of these
Answer. All of these
21. Humans need air conditioning because …..
• They continuously radiate heat due to metabolic activity
• The systems that regulate the body need to maintain a constant internal temperature
• Efficiency is increased under controlled conditions
• All of these
Answer. All of these
22. The chemical formula of refrigerant R11 is ….
• CCI3F
• CCIF3
• CCIFH
• CHF
Answer. CCI3F
23. Which of the following refrigerant replaces R12 in domestic refrigerators?
• R22
• R11
• R134a
• R141b
Answer. R134a
24. What role does ice play in interacting with air conditioning?
• Ice is needed to keep the compressor cool
• Ice is needed to keep the refrigerant cool
• This is a new “green” method of air conditioning
• None of the above
Answer. This is a new “green” method of air conditioning
25. What is the reason for refrigerant getting contaminated?
• Moisture in the refrigerant
• Low oil level
• High oil level
• Lack of gas
Answer. Moisture in the refrigerant
26. Which thermometer helps in finding the relative humidity?
• Dial thermometer
• Mercury thermometer
• Alcohol thermometer
• Dry and wet bulb thermometer
Answer. Dry and wet bulb thermometer
27. Which of the following charts shows the relative humidity?
• Temperature chart
• Psychrometric chart
• Chilled water chart
• Condenser water chart
Answer. Psychrometric chart
28. What are the advantages of central AC plant?
• Low initial cost
• Air supply is centralized
• Individual de-humidification
• Room temperature remains constant
Answer. Air supply is centralized
29. Large size fans are equipped with ………
• Low capacity requirements
• Directly connected motors
• Squirrel cage house
• ”V belt drive
Answer. ”V belt drive
30. Centrifugal fan consists of an impeller and a …….
• Belt
• Housing
• Duct line
• Damper adjustment
Answer. Housing
31. Which type of fan is used in electric motors for internal cooling?
• Backward inclined fan
• Backward coiled fan
• Forward curled fan
• Radial blade fan
Answer. Radial blade fan
32. The temperature at which moisture solidifies on the surface is called ……….
• Moisture grain
• Wet bulb temperature
• Dry bulb temperature
• Dew point temperature
Answer. Dew point temperature
33. Which type of coat is applied on ducts fabricated from mild steel?
• Oil
• Epoxy
• Paint
• Powder
Answer. Epoxy
34. The gap between false ceiling and main ceiling is referred to as ………
• Supply air duct
• Return damper
• Diffuser
• Plenum
Answer. Plenum
35. Which filter removes tobacco, smoke and other odors?
• Pre-filter
• Film filter
• Coarse filter
• Electronic filter
Answer. Electronic filter
36. What will happen if the ducted split AC condenser becomes very dirty?
• The room will become cold
• The compressor will trip
• The room will become very hot
• The AC will keep running continuously
Answer. The compressor will trip
37. What controls the flow of refrigerant in a ducted split AC?
• Evaporator
• Thermostat
• Compressor
• Expansion device
Answer. Expansion device
38. What is the reason for low air flow rate in a multi split AC unit?
• Sunlight entering the room
• Gas on windows or doors
• Partially choked air filter
• No air return
Answer. Partially choked air filter
39. When the LP switch trips the package AC is ………..
• Liquid line pressure
• Low suction pressure
• High suction pressure
• Low discharge pressure
Answer. Low suction pressure
40. The sediment which forms a coating on the cooling coils will reduce the ……….
• Temperature
• Suction pressure
• Heat transfer efficiency
• Heat load on the evaporator or chiller
Answer. Heat transfer efficiency
41. Which type of material is used on the line which circulates acid for de-scaling?
• GI pipe
• PVC pipe
• Copper pipe
• Aluminium pipe
Answer: PVC pipe
42. Which type of arrangement negates the odour entering the AHU through the drain line?
• NRV
• s trap
• U Trap
• Shut off valve
Answer. U Trap
43. Which provides the opportunity to cool the room independently while using a central AC plant?
• Air Washer
• Fan Coil Unit
• Air Handling Unit –
• Indirect Cooling Unit
Answer. Fan Coil Unit
44. Which arrangement negates the introduction of water along with cool air in an air washer?
• Basin
• Filter
• Blower
• Eliminator
Answer. Eliminator
45. What is the best function of a fan selected for a duct system?
• Heavy vibration
• Maximum throw
• Minimum noise
• Fast movement
Answer. Minimum noise
46. What are the fans and blowers used for in a central AC plant?
• Heating
• Cooling
• Circulation of air
• Circulation of chilled water
Answer. air circulation
47. Which type of humidifier has the advantage of no scale formation?
• Electrode humidifier
• Steam pan humidifier
• Spray type humidifier
• Water automating humidifier
Answer. Electrode humidifier
48. Solenoid valve in suction line gives…….?
• Partial flow
• Limited flow
• Steady flow
• Interrupted flow
Answer. Steady flow
49. During defrosting of hot gas ………..
• Heater remains on
• Water spray will remain open
• Compressor will run
• Solenoid valve will remain closed
Answer. Compressor will run
50. What would be the reason for poor cooling in a central plant?
• There is no gas in the system
• Lube-oil level is high
• Gas is leaking slowly
• Cooling tower fan is running fast
Answer. Gas is leaking slowly
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