ITI RAC Theory 1st Semester Exam Paper
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 1st 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.
ITI RAC Theory 2nd Semester Exam Papers
1. The condenser surface is generally finned to………..
• Decrease in heat loss
• Increase in heat loss
• Enhance beauty
• None of these
Answer: Increase in heat loss
2. Undercharging of refrigerant in a refrigerator will cause which of the following?
• Increase in COP
• Decrease in COP
• Increase in capacity
• None of these
Answer: Decrease in COP
3. Sub-chilling is the process by which the temperature of ….. is reduced.
• Superheated refrigerant leaving the compressor
• Refrigerant leaving the expansion valve value
• Refrigerant leaving the condenser in saturated state
• Refrigerant leaving the evaporator
Answer. Refrigerant leaving the condenser in saturated state
4. The first law of thermodynamics defines the property of…….
• Energy
• Ex
• Entropy
• Enthalpy
Answer: Energy
5. In a series circuit :
• Equal current flows through each resistor
• Voltage drops across each resistor
• Total resistance is the sum of the resistances of the individual resistors
• All of the above
Answer: All of the above
6. In lap joint:
• Plates are joined at the ends
• Plates are placed one above the other
• One plate is placed horizontally
• Others are placed vertically
Answer. Plates are placed one above the other
7. Energy meter is used for measuring the following:
• Power
• Resistance
• Current
• Voltage
Answer. Power
8. The refrigerant traditionally used in refrigerators is:
• R11
• R143
• R13
• None of these
Answer: None of these
9. Pressure = ………
• Force per unit time
• Force per unit length
• Force per unit area
• Force per unit area
Answer: Force per unit area
10. Mallet is a …….
• Hard hammer
• Soft hammer
• Smoothing harmer
• Tensile hammer
Answer: Soft hammer
11. The temperature range of the evaporator coil in a refrigerator is:
• 0 to 10°C
• 0 to 5°C
• -5 to 5°C
• None of these
Answer: None of these
12. When there are capacitors and inductors in an AC circuit, the relation between voltage and current is:
• Current leads voltage by 45°
• Voltage leads current by 90°
• Current leads voltage by 90°
• Voltage leads current by 45°
Answer. The current leads the voltage by 45°
13. Snips are used for:
• Measuring tools
• Marking tools
• Cutting tools
• Supporting tools
Answer: Cutting tool
14. In the refrigeration cycle the heat flow is :
• From high temperature to low temperature
• From low temperature to high temperature
• From compressor to evaporator
• From liquid line to evaporator
Answer. From low temperature to high temperature
15. Pressure testing is done by using…….
• Air
• Steam
• Nitrogen
• Hydrogen
Answer: Nitrogen
16. The coefficients of efficiency of a refrigeration system are the ratio of…..
• Cooling effect from power input
• Cooling effect from energy input
• Heating effect from power input
• Heating effect from energy input
Answer. Cooling effect depends on energy input
17. The angle of a centre punch is :
• 450
• 75°
• 90°
• 15°
Answer. 90°
18. With oxyacetylene welding the temperature in the neutral flame is:
• 3260°C
• 3500°C
• 2500°C
• 2800°C
Answer. 3260°C
19. The best conductor of electricity is:
• Silicon
• Copper
• Aluminium
• Gold
Answer: Copper
20. The unit of frequency is :
• Second
• Curie
• Tesla
• Hertz
Answer: Hearts
21. Star-delta starting of motor is not possible in case of……..
• Single phase motors
• Variable speed motors
• Low horsepower motors
• High speed motors
Answer: Single phase motor
22. Delta connection is done when :
• When the starting point of one coil is connected to the end point of other coil
• All the starting points of the coils are connected to each other
• When the starting point and ending point of each coil are not connected
• None of these
Answer. The starting point of one coil is connected to the end point of the other coil
23. If Ns is synchronous speed and s is slip, then what will be the actual speed of running of induction motor?
• Ns
• S.N
• (1 – s) Ns
• (Ns – 1)s
Answer. (1 – s) Ns
24. The most important property of a refrigerant is:
• High latent heat of vaporization
• Low viscosity
• Chemically stable
• Non-toxic
Answer: High latent heat of vaporization
25. Refrigeration is based on……..
• First law of thermodynamics
• Kelvin Planck’s statement of the second law of thermodynamics
• Clausius’ statement of the second law of thermodynamics
• Third law of thermodynamics
Answer. Clausius’ statement of the second law of thermodynamics
26. Double door refrigerators operate on…….
• Vapour Compression Cycle
• Air Refrigeration Cycle
• Vapour Absorption Cycle
• Ejector Refrigeration Cycle
Answer: Vapour compression cycle
27. In the evaporator of a refrigeration system, the refrigerant is transformed into……..
• From vapor to liquid
• From liquid to vapor
• Remains in liquid form
• None of these
Answer. From liquid to vapor
28. GI sheets are measured:
• By sheet gauge
• By plug gauge
• By feeler gauge
• By vernier height gauge
Answer: By sheet gauge
29. Rubber is an example of……
• convector
• conductor
• heater
• insulator
Answer: Insulator
30. In the process of latent heat, the temperature……..
• Remains constant
• Increases
• Decreases
• May increase or decrease depending upon the direction of heat transfer speed
Answer: remains constant
31. In vapour compression system the low pressure side has…….
• Suction line
• Evaporator
• Discharge line
• Both (a) and (b)
Answer: Both (a) and (b)
32. In oxidizing welding flame……..
• The ratio of acetylene is less than air
• The ratio of air is less than acetylene
• The ratio of acetylene and air remains the same
• None of these
Answer. The proportion of acetylene is less than that of air
33. Refrigerant When using ammonia as a refrigerant, the piping is normally made of……
• Copper
• Aluminium
• Bronze
• Steel
Answer. Steel
34. The cross-section of a capillary tube from its inlet to its outlet is……..
• Increases
• Decreases
• Remains constant
• None of these
Answer: remains constant
35. Ammeter is used for:
• In series in a circuit
• In parallel in a circuit
• In the earth wire
• None of these
Answer. In series in a circuit
36. The equivalent value of unit of refrigeration is :
• 210 kJs
• 3.5 kw/s
• 210 kJ/min
• 3.5 W/hr
Answer. 210 kJ/min
37. Which of the following is a cutting tool?
• Steel rule
• Surface plate
• Chisel
• Pipe vice
Answer: Chisel
38. In an AC circuit, the power factor is the ratio of…….
• Apparent power is the power that is being used to do work and the actual power supplied to the circuit
• Real power is the power that is being used to do work and the apparent power supplied to the circuit
• Reactive power is the power that is being used to do work and the apparent power supplied to the circuit
• Real power is the power that is being used to do work and the reactive power supplied to the circuit
Answer. Real power being used to do work and apparent power supplied to the circuit
39. Atmospheric pressure is equal to……
• 101.325 kPa
• 9.81 kgt/cms
• 750 mm of Mercurial column.
• None of these
Answer. 101.325 kPa
40. Tapes are used for :
• For cutting external threads
• For drilling holes
• For producing internal threads
• For measuring the internal diameter of holes
Answer: For producing internal threads
41. The refrigerant used in window type air conditioners is:
• Ammonia
• R-22
• R-134a
• Propane
Answer. R-22
42. The compressor capacity of a 165 litre refrigerator is approximately……..
• 1 TR
• 2 TRI
• 0.1 TR.
• 0.5 TR
Answer. 0.1 TR.
43. Capillary tube…….
• Increases pressure
• Decreases pressure
• Increases temperature
• None of these
Answer: decreases the pressure
44. The frame of an induction motor is generally made of………..
• Brass
• Gold
• Aluminium
• None of these
Answer: None of these
45. Grinding is mainly used for……
• Rough finishing
• Semi rough finishing
• Fine finishing
• None of these
Answer. Beautiful finishing
46. TPL is used for:
• Turns per inch
• Threads per inch
• Tapers per inch
• Teeth per inch
Answer: Threads per inch
47. 18 The thickness of SwG sheet is:
• 2 mm.
• 3 mm.
• 1.5 mm.
• 1.2 mm.
Answer. 1.2 mm.
48. The most suitable refrigerant is that which has……
• ORP =1
• ORP = 0.5
• ORP = 0.75
• ORP = 0
Answer. RESP = 0
49. The compressor used in refrigerator is?
• hermetically sealed reciprocating compressor
• semi hermetically sealed reciprocating compressor
• open type compressor
• centrifugal compressor
Answer. Hermetically sealed reciprocating compressor
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