| Post Name | JUNIOR INSTRUCTOR(MECHANIC REFRIGERATION AND AIR CONDITIONING) |
|---|---|
| Question Paper Code | 123/2024 |
| Category Code | 665/2023, 729/2023 |
| Date of Test | 9 September 2024 |
| Medium of Question | ENGLISH |
| Exam Type | OMR Examination |
| Total Questions | 100 |
1
Which of the following statement is/are correct about first aid for burn ?
i. Use creams or ointments immediately if the burn is second degree.
ii. If the burn is third degree, should be covered with a damp cloth.
iii. Immersing or flushing with cool water if the burn is first degree.
Answer
A. Only ii and iii
2
As per Indian Standard, kitchen fires (fire involve combustible cooking media such
as vegetable or animal oils and fats) are categorised under
Answer
C. Class F
3
Which of the following statement is/are correct about a ball pein hammer ?
i. The wedges fix the handle in the eyehole.
ii. The weight of the hammer is stamped on face.
iii. Hammer is made of drop-forged carbon steel.
Answer
C. Only i and iii
4
The included angle of the V in V-block is
Answer
A. 90 degree
5
In a vernier caliper, 9 main scale divisions are divided into 10 equal parts in the
vernier scale. Value of one main scale division is 1 mm. What is the least count of
this vernier caliper ?
Answer
B. 0.1 mm
6
Which of the following statement is/are correct about standard wire gauge ?
i. The thickness of the sheet and diameter of wire are measured with the help of
the standard wire gauge
ii. Smaller gauge numbers representing small size, higher gauge number
representing larger sizes
iii. Wire diameter is checked by inserting the wire on the circle portion of the
gauge.
Answer
D. Only i
7
Which stake is used for turning up flanges on metal discs ?
Answer
B. Half moon stake
8
Which of the following statement is/are correct in case of oxy-acetylene gas welding ?
i. Soap water is used to check the leakage in the acetylene regulator connections
ii. Colour of oxygen gas cylinder is black
iii. Oxygen gas cylinder valves have right hand thread.
Answer
D. All of the above i, ii and iii
9
Which is used to convert AC into DC in AC welding transformer ?
Answer
B. Rectifier
10
Which type of joint is used for extending the length of conductor in over head lines ?
Answer
D. Western Union Joint
11
What is the value of resistance in an open circuit ?
Answer
A. Infinity
12
Which of the following capacitors is marked for polarity ?
Answer
C. Electrolytic
13
Where the capacitor is connected in a single phase permanent capacitor motor ?
Answer
B. In series with starting winding
14
What is the application of shaded pole motor ?
Answer
C. Hair dryer
15
What is the function of centrifugal switch in single phase motor ?
Answer
B. make a break the starting winding from supply
16
What is the function of timer in automatic star delta starter ?
Answer
A. Change from star to delta
17
What is the purpose of using rotor resistance starter to start 3 phase slip ring induction
motor ?
Answer
D. Increase the torque
18
A semiconductor has
Answer
B. Negative temperature co-efficient of resistance
19
What is the main use of a Zener diode ?
Answer
C. Voltage regulation
20
One ton of refrigeration is equal to
Answer
A. 210 KJ/min.
21
The sub-cooling is a process of cooling the refrigerant
Answer
C. Before throttling
22
The refrigerant commonly used in vapour absorption system is
Answer
C. Aqua-ammonia
23
The compression device used in a steam jet refrigeration system is
Answer
D. Steam ejector
24
The refrigerant R-764 stands for
Answer
B. Sulphur dioxide
25
The wrench used when odd sizes of the nuts and bolts heads are to be handled is
Answer
A. Adjustable Wrench
26
1 bar is equal to
Answer
C. 105 N/m2
27
The law which is used to understand the concept of energy conservation is
Answer
A. First law
28
The volume of a given mass of a perfect gas varies directly as its absolute temperature,
when the absolute pressure remains constant. This statement belongs to
Answer
B. Charle’s law
29
The coefficient of performance is always
Answer
C. Greater than one
30
during a refrigeration cycle, heat is rejected by the refrigerant in a
Answer
B. Condenser
31
The function of halide torch is
Answer
D. detecting leakage of refrigerant
32
The reciprocating compressors are suitable for
Answer
A. Small displacement and high condensing pressure
33
A thrust bearing is generally used in
Answer
B. Centrifugal refrigerant compressor
34
Centrifugal refrigerant compressors are employed for the following refrigerant
Answer
D. R-113
35
In a double pipe condenser
Answer
Question Cancelled
36
For ammonia refrigerating system, the tubes of a shell and tube condenser are
made of
Answer
C. Steel
37
The condensing medium used in evaporative condenser is
Answer
C. Both air and water
38
The evaporator generally used in domestic refrigerators and frozen food industry is
Answer
D. Plate evaporator
39
The capillary tube expansion device is used in
Answer
D. All of the above
40
The refrigerant supplied to a compressor must be
Answer
B. Super-heated vapour refrigerant
41
Which of the following compressor is generally used in domestic refrigerator ?
Answer
C. Reciprocating
42
In a domestic refrigerator, periodic defrosting is required because frosting
Answer
A. Reduces heat extraction
43
direct expansion coil evaporator is
Answer
A. dry type evaporator
44
In a refrigeration system, the expansion device is connected between
Answer
C. Receiver and evaporator
45
With thermostatic expansion valve used in vapour compression refrigeration system,
if the discharge pressure is very high, the reason is
Answer
D. All of the above
46
An evaporator is also known as
Answer
D. All of these
47
most thermostatic expansion valve are set for a superheat of
Answer
A. 5°C
48
OdP is a factor based on the percentage weight of ____________ in a compound
and its life time (stability) in the atmosphere.
Answer
B. Chlorine
49
While numbering the refrigerant R134a, the first number on the right side is the
number of ___________ atoms in that refrigerant.
Answer
A. Fluorine
50
What is the cylinder colour code of Refrigerant R 410A ?
Answer
C. Rose
51
Boiling point of R22 is
Answer
D. –41°C
52
State the leak detection method which involves burning of fuel gas near a copper
plate and using a rubber hose to siphon air from areas suspected of a leaking
refrigerant.
Answer
A. Halide torch leak detection
53
mention the type of evaporator which usually have Aluminium plate type coil and
have no fins which is used in conventional refrigerators.
Answer
B. Static type evaporators
54
The relay coil and compressor motor starting windings are connected in series. What
is the function of a relay in a refrigerator wiring circuit ?
Answer
D. disconnect starting winding
55
The test pressure of a refrigerator is based on _________ pressure of the system.
Answer
C. discharge pressure
56
Which electrical device activates the heater and stops the compressor, condenser
fan and evaporator fan during defrosting period ?
Answer
B. Timer
57
State the name of the component which turns off the heater after the defrost period
in a frost free refrigerator
Answer
C. Bimetal thermostat
58
In a BLDC motor which component generates a DC magnetic field instead of AC
magnetic field that is produced by passing AC current through an electro magnet ?
Answer
D. Permanent magnet
59
Which type of expansion device is used in a storage type water cooler ?
Answer
A. Capillary tube
60
What type of mechanism provided to reduce the water inlet temperature before
entering the evaporator tank in an instantaneous type water cooler ?
Answer
B. Pre cooler
61
How many running capacitors are used in a CSIR wiring circuit of a visible cooler ?
Answer
C. Running capacitors are not used
62
What is the usual operation temperature range of a Deep Freezer ?
Answer
D. –15°C to – 34°C
63
Which among the following is the reason not to trip a deep freezer ?
Answer
B. Sufficient refrigerant in the system
64
What is the maximum incoming water pressure of an ice cube machine ?
Answer
A. 60 PSI
65
Name the electrically operated switch/control instrument which controls the
temperature of a refrigerated space or product by cycling the compressor.
Answer
C. Thermostat
66
State the term related to a window air conditioner’s performance ratio that expresses
cooling capacity in BTU/Hr for each watt of power consumed.
Answer
D. Energy Efficiency Ratio (EER)
67
An air conditioner which is working with the help of a potential relay used in its wiring
circuit, connection of start capacitor should be with ____________ terminal of the
relay.
Answer
B. Terminal 1
68
Name the evacuation method in which uses a vacuum pump to pull a vacuum of
250 microns
Answer
C. Deep vacuum
69
How to place the refrigerant cylinder to charge with vapour refrigerant into an air
conditioning systems low side ?
Answer
A. Upright position
70
Which one is correct for an outdoor unit of a split air conditioner ?
Answer
D. Compressor, Fan motor, Condenser, Service valves
71
What is the normal running current of a split air conditioner having capacity 1.5 TR ?
Answer
A. 8.5 Amps
72
Which arrangement helps an air conditioning system to increase sub cooling and
decrease flash-gas of refrigerant ?
Answer
C. liquid suction heat exchanger
73
Which switch opens its contact and stops the compressor motor when the suction
pressure or evaporator pressure falls ?
Answer
B. low pressure cut out switch
74
An inverter equipped split air conditioner have a __________ that incorporate an
adjustable inverter to control speed of compressor motor and cooling output of
system.
Answer
A. VFd
75
The important part used in an ice candy machine for freezing the candy is
Answer
D. ice can
76
Which refrigerant is commonly used in commercial ice plant ?
Answer
C. Ammonia
77
What is the function of brine agitator in an ice plant ?
Answer
A. To obtain uniform temperature
78
Which component is used to maintain a constant temperature in walk in cooler ?
Answer
C. Thermostat
79
The process of removing moisture from the food product is called
Answer
D. dehydration
80
Generally used method for protecting milk against bacterial infection is
Answer
C. Pasteuriation
81
leakage in the vapour compression refrigeration system using ammonia as
refrigerant is detected by
Answer
A. sulphur candle
82
The difference between dry bulb temperature and wet bulb temperature is called
Answer
C. wet bulb depression
83
Generally used process in summer air conditioning is
Answer
B. Cooling and dehumidification
84
The ratio of sensible heat to total heat is known as
Answer
C. Sensible heat factor
85
On a psychrometric chart sensible cooling is represented by
Answer
A. Horizontal line
86
The conditioned air supplied to the room must have the capacity to take up
Answer
C. room sensible heat and latent heat load
87
The difference in temperature of the warm water and the cold water in the cooling
tower is called
Answer
B. cooling tower range
88
Which one is the daily maintenance in central air conditioning ?
Answer
D. Check cooling air water and refrigerant temperatures
89
Package air conditioners are found in normal capacity up to
Answer
A. 15 Tons
90
An air conditioner in which one or more assemblies are disassembled from other
assemblies is called
Answer
C. Split Unit
91
A duct is said to be a low velocity duct if the velocity of air in the duct is up to
Answer
A. 800 m/min
92
For rectangular ducts the aspect ratio is equal to
Answer
C. Ratio of longer and shorter sides
93
Which type of duct requires least material for carrying air ?
Answer
A. Circular
94
The axial flow fans are particularly suitable for handling
Answer
A. large volume of air at relatively low pressure
95
The air filtered by electronic filter is passed from
Answer
D. Electrostatic field
96
What is the percentage efficiencies in fine filter ?
Answer
D. 99.90%
97
Which filter removes tobacco smoke and other odours ?
Answer
A. Electronic filter
98
Which component engage and disengage the compressor with thermostat in an
automobile air conditioner ?
Answer
B. magnetic clutch
99
The AC of a car air conditioning system can be regarded as
Answer
A. dX system
100
What is the reason for water dripping inside the air conditioned bus ?
Answer
B. Poor insulation at the bottom of drain pan
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