Refrigeration Mechanic Exam Question Paper with Answer- 100 Nos

Examination: Refrigeration Mechanic UIP

Date of Exam: 04-04-2023

Department: Department Health Services

Answers: Answers available below each questions

Number of Questions: 100

Refrigeration Mechanic Exam Question Paper with Answer Page 1

Question1:-The pressure of a gas, which just sufficient to liquefy the gas below its
critical temperature is
A:-Vacuum pressure
B:-Discharge pressure
C:-Critical pressure
D:-Absolute pressure
Correct Answer:- Option-C

Question2:-In first aid CPR stands for
A:-Cardio Pulmonary Resuscitation
B:-Cardio Physio Resuscitation
C:-Cardio Pulmonary Respiration
D:-None of the above
Correct Answer:- Option-A

Question3:-The weight of an Engineer’s hammer is stamped at its
A:-Face
B:-Pein
C:-Cheek
D:-Eye hole
Correct Answer:- Option-C

Question4:-The selection of a hacksaw blade depends upon the ________ of the
metal to be cut.
A:-Shape and hardness
B:-Thickness and elasticity
C:-Size and toughness
D:-Length and rigidity
Correct Answer:- Option-A

Question5:-_________ is measured by using a vernier height gauge along with a dial
indicator.
A:-External dimension
B:-Width of slot
C:-Depth
D:-Pitch dimension
Correct Answer:- Option-D

Question6:-The cutting angle of straight snips is
A:-52°
B:-87°
C:-70°
D:-45°
Correct Answer:- Option-B

Question7:-The joining allowance for knocked-up-joint is
A:-K = 2W + 2T
B:-K = 2W + 4T
C:-K = 2W + 5T
D:-K = 2W + 3T
Correct Answer:- Option-D
Question8:-How much pressure you will set on the regulator for oxygen gas for
fusion run with filler road on 3.15 mm thick mild steel sheet ?
A:- 0.15 kgf/cm
B:-0.18 kgf/cm
C:-0.19 kgf/cm
D:-0.17 kgf/cm
Correct Answer:- Option-A
Question9:-Which of the following is an example of plastic welding ?
A:-Forge welding
B:-Thermit welding
C:-Laser welding
D:-Electron beam welding
Correct Answer:- Option-A

Question10:-Which error if the energy meter disc rotating continuously on no load ?
A:-Speed error
B:-Phase error
C:-Friction error
D:-Creeping error
Correct Answer:- Option-D

Refrigeration Mechanic Exam Question Paper with Answer Page 2

Question11:-What happens to the voltmeter if it is connected as an ammeter ?
A:-Low reading
B:-No deflection
C:-Meter burns out
D:-Overshoot deflection
Correct Answer:- Option-A
Question12:-Which conductors are used for distribution lines ?
A:-Insulated conductors
B:-Insulated solid conductors
C:-Bare conductors
D:-Two core cable
Correct Answer:- Option-C
Question13:-What is the advantage of stranded conductor over solid conductor ?
A:-Cost is less
B:-More flexible
C:-Less voltage drop
D:-More insulation resistance
Correct Answer:- Option-B
Question14:-Which principle the earth resistance tester works ?
A:-Self induction
B:-Mutual induction
C:-Fall of potential method
D:-Fleming’s left hand rule
Correct Answer:- Option-C
Question15:-Which type of single phase motor is having very high starting torque
than any other type of single phase motor ?
A:-Universal motor
B:-Reluctance motor
C:-Repulsion start induction run motor
D:-Capacitor start induction run motor
Correct Answer:- Option-A
Question16:-Which speed is called as synchronous speed in three phase induction
motor ?
A:-No load speed
B:-Full load speed
C:-Rotating magnetic field
D:-Relative speed between stator and rotor
Correct Answer:- Option-C
Question17:-What is the purpose of using rotor resistance starter to start three
phase slip ring induction motor ?
A:-Reduce rotor voltage
B:-Reduce rotor current
C:-Increase the torque
D:-Reduce the power loss
Correct Answer:- Option-C
Question18:-Which is an active component ?
A:-Inductor
B:-Resistor
C:-Capacitor
D:-Transistor
Correct Answer:- Option-D
Question19:-Which is the main application of SCR ?
A:-Amplifier
B:-Oscillators
C:-Multi vibrators
D:-Speed control of motors
Correct Answer:- Option-D
Question20:-Which material is used to make cutting wheel in a tube cutter ?
A:-Steel
B:-Cast iron
C:-Aluminium alloy
D:-Carbon steel
Correct Answer:- Option-D

Refrigeration Mechanic Exam Question Paper with Answer Page 3

Question21:-Which instrument is used to check the clearance between cylinder wall
and piston of a reciprocating compressor ?
A:-Screw gauge
B:-Feeler gauge
C:-Radius gauge
D:-Sheet gauge
Correct Answer:- Option-B
Question22:-Which instrument is used to find the relative humidity of air ?
A:-Gauge manifold
B:-Pressure gauge
C:-Sling Psychrometer
D:-Micron gauge
Correct Answer:- Option-C
Question23:-How much degree angle is cut out on the face of each hole in a flare
block ?
A:-45°
B:-55°
C:-65°
D:-120°
Correct Answer:- Option-A
Question24:-One calorie, is the amount of heat required to raise the temperature of
1 gram of water through
A:-1°F
B:-5°C
C:-4°C
D:-1°C
Correct Answer:- Option-D
Question25:-The volumetric efficiency of the compressor is defined as the ratio of
A:-Absolute discharge pressure to the absolute suction pressure
B:-Clearance volume to the piston displacement volume
C:-Theoretically calculated volume to actual volume
D:-The suction volume to the piston displacement volume
Correct Answer:- Option-D
Question26:-Sub cooling is the process of reducing the temperature of liquid
A:-Refrigerant leaving the evaporator
B:-Refrigerant leaving the compressor at Super heated state
C:-Refrigerant leaving the expansion valve
D:-Refrigerant below its saturation temperature
Correct Answer:- Option-D
Question27:-Super heating is
A:-Cooling of vapour below it’s condensing point
B:-Heating of vapour above its boiling point
C:-Heating of liquid up to the boiling point
D:-Heat required to change the state
Correct Answer:- Option-B

Question28:-Which law of thermodynamics states that at constant volume, the
absolute pressure of a given mass of a perfect gas varies directly to its absolute
temperature ?
A:-Zeroth law
B:-Boyle’s law
C:-Gay-lussac law
D:-Charle’s law
Correct Answer:- Option-C

Question29:-Three TR is equivalent to ______ of cooling effect.
A:-10.5 KW
B:-3.5 KJ/second
C:-232.6 KJ/min
D:-7.5 KW

Correct Answer:- Option-A

Question30:-Which refrigeration system called as expandable refrigerant
refrigeration system ?
A:-Water vapour system
B:-Liquid gas refrigeration system
C:-Dry ice refrigeration system
D:-Steam jet refrigeration system
Correct Answer:- Option-B

Refrigeration Mechanic Exam Question Paper with Answer Page 2

Question31:-What is the name of the process in which dry ice is converted into
vapour state ?
A:-Sub cooling
B:-Super heating
C:-Sublimation
D:-Quick freezing
Correct Answer:- Option-C

Question32:-Which compressor dome handles high pressure and high temperature
vapour ?
A:-Hermetic rotary compressor
B:-Semi hermetic reciprocating compressor
C:-Open type reciprocating compressor
D:-Hermetic reciprocating compressor
Correct Answer:- Option-A

Question33:-The range of a cooling tower is the difference between
A:-Inlet water temperature and Outlet water temperature
B:-Outlet water temperature and Ambient air temperature
C:-Inlet water temperature and Ambient air temperature
D:-Ambient air temperature and temperature of air leaving cooling tower
Correct Answer:- Option-A
Question34:-Which type of compressor is provided with slide valve mechanism for
capacity control ?
A:-Reciprocating
B:-Screw
C:-Centrifugal
D:-Rotary
Correct Answer:- Option-B
Question35:-Which part of a centrifugal compressor converts velocity pressure into
static pressure ?
A:-Impeller
B:-Rotor
C:-Diffuser
D:-Whirl vane mechanism
Correct Answer:- Option-C

Question36:-Which compressor is known as turbo compressor in air conditioning
systems ?
A:-Rotary
B:-Screw
C:-Centrifugal
D:-Scroll
Correct Answer:- Option-C
Question37:-Leaking tubes of a water cooled condenser are isolated using
A:-Brass plugs
B:-Hard rubber bushes
C:-Mild steel plugs
D:-Wooden plugs
Correct Answer:- Option-A
Question38:-Which type of condenser uses air and water as cooling medium ?
A:-Tube in tube condenser
B:-Evaporative condenser
C:-Shell and tube condenser
D:-Forced convection air cooled condenser
Correct Answer:- Option-B
Question39:-The process of removing accumulated minerals and unwanted
materials from the tubes of a water cooled condenser is called
A:-Defrosting
B:-Deburring
C:-Descaling
D:-Retrofitting
Correct Answer:- Option-C
Question40:-What is the name of the operation used to reduce the salt
concentration in cooling tower water ?
A:-Descaling
B:-Blow down
C:-Ozonisation
D:-Bleed off
Correct Answer:- Option-D

Refrigeration Mechanic Exam Question Paper with Answer Page 5

Question41:-What will be the approach of a cooling tower if the inlet water
temperature is 36°c, outlet water temperature is 30°c and ambient wet bulb
temperature is 25°c ?
A:-10°C
B:-5°C
C:-6°C
D:-11°C
Correct Answer:- Option-B
Question42:-GI sheets used for making ducts, are made resistant to rust by coating
with
A:-Zinc
B:-Copper
C:-Aluminium
D:-Tin
Correct Answer:- Option-A
Question43:-Equaliser tube is a part of
A:-Level master control
B:-Automatic expansion valve
C:-Thermostatic expansion valve
D:-Electronic expansion valve
Correct Answer:- Option-C
Question44:-Which expansion device controls the refrigerant flow according to
evaporator pressure ?
A:-High side float valve
B:-Automatic expansion valve
C:-Thermostatic expansion valve
D:-Electronic expansion valve
Correct Answer:- Option-B
Question45:-Which of the following expansion device cannot change the quantity of
refrigerant according to the load ?
A:-High side float valve
B:-Low side float valve
C:-Thermostatic expansion valve
D:-Capillary tube
Correct Answer:- Option-D
Question46:-Operating temperature of frosting type evaporator is
A:-Below 32°F
B:-Above 32°F
C:-Above 0°C
D:-Below 212°F
Correct Answer:- Option-A
Question47:-What is the other name of bare tube coil evaporator ?
A:-Fins evaporator
B:-Tube in tube evaporator
C:-Prime surface evaporator
D:-Shell and coil evaporator
Correct Answer:- Option-C
Question48:-Which type of evaporator is used in direct cool refrigerator ?
A:-Plate type
B:-Bare coil
C:-Fin and tube
D:-Pipe in pipe
Correct Answer:- Option-A
Question49:-Which component provide necessary pumping action to refrigerant in
direct cool refrigerator ?
A:-Expansion device
B:-Filter drier
C:-Accumulator
D:-Compressor
Correct Answer:- Option-D
Question50:-Which of the following statement is correct about the desirable
property of refrigerant ?
A:-It must have low dielectric strength
B:-It must have high latent heat value
C:-It must not miscible with Lubricant
D:-It must have high freezing point
Correct Answer:- Option-B

Refrigeration Mechanic Exam Question Paper with Answer Page 6

Question51:-Which of the following statement is correct about the heat insulating
material ?
A:-It must have high heat conductivity
B:-It must have low heat conductivity
C:-It must have high moisture absorbing capacity
D:-It must have capacity to absorb fungus and vermin
Correct Answer:- Option-B
Question52:-Which part meter and regulate the pressure of refrigerant admitted to
the evaporator ?
A:-Filter drier
B:-Muffler
C:-Capillary tube
D:-Accumulator
Correct Answer:- Option-C
Question53:-Which part protect the compressor from the damage due to the high
current consumption ?
A:-OLP
B:-LMS Relay
C:-Thermostat
D:-Door switch
Correct Answer:- Option-A
Question54:-Which substance is known as heat carrying medium in refrigeration
system ?
A:-PUFF
B:-Refrigerant
C:-Silica gel
D:-Activated carbon
Correct Answer:- Option-B
Question55:-Which one is example of primary refrigerant ?
A:-Sodium chloride solute
B:-Calcium chloride
C:-Ammonia
D:-Glycol
Correct Answer:- Option-C
Question56:-What is the chemical name of R134a refrigerant ?
A:-Trifluoromethane
B:-Dichlorodifluoromethane
C:-Dichlorotrifluoromethane
D:-Tetrafluoroethane
Correct Answer:- Option-D
Question57:-What is the boiling point of isobutene refrigerant (R600a) ?
A:-?26°C
B:-22°C
C:-?12°C
D:-16°C
Correct Answer:- Option-C
Question58:-What is the normal ratio of R600a and R290 refrigerant in HC blend ?
A:-50:50
B:-25:75
C:-75:25
D:-35:65
Correct Answer:- Option-A
Question59:-Which lubricant is used with R134a Refrigerant ?
A:-Mineral oil
B:-Wax oil
C:-Paraffin oil
D:-Polyol ester oil
Correct Answer:- Option-D
Question60:-Which component prevent the liquid refrigerant entering the
compressor ?
A:-Filter drier
B:-Muffler
C:-Accumulator
D:-Capillary tube
Correct Answer:- Option-C

Refrigeration Mechanic Exam Question Paper with Answer Page 7

Question61:-Which type of Vacuum pump can generate a vacuum of 20 to 50
microns ?
A:-Reciprocating
B:-Double stage rotary
C:-Single stage rotary
D:-Scroll
Correct Answer:- Option-B
Question62:-Which type of relay is used with Capacitor start capacitor run sealed
compressor motor ?
A:-LMS relay
B:-Current coil relay
C:-Potential relay
D:-Centrifugal relay
Correct Answer:- Option-C
Question63:-In pump down process in split AC, where did the refrigerant stored ?
A:-Condenser
B:-Evaporator
C:-Accumulator
D:-Metering device
Correct Answer:- Option-A
Question64:-What is the GWP of R 22 Refrigerant ?
A:-500
B:-7300
C:-1300
D:-1700
Correct Answer:- Option-D
Question65:-Which refrigerant is the HFC group Zeotropic Mixture ?
A:-R290a
B:-R502
C:-R407C
D:-R123
Correct Answer:- Option-C
Question66:-What is the purpose of soldering the capillary tube to the suction line
in frost free refrigerator ?
A:-Super heating vapour and sub cooling liquid
B:-Sub cooling vapour and liquid
C:-Super heating liquid and sub cooling vapour
D:-Super heating vapour and liquid
Correct Answer:- Option-A
Question67:-What is the use of desiccants in filter drier ?
A:-Absorb refrigerant
B:-Absorb lubricant
C:-Absorb acid
D:-Absorb moisture
Correct Answer:- Option-D
Question68:-Which type of defrosting method is used in frost free refrigerator ?
A:-Electric heater method
B:-Reverse cycle method
C:-Manual method
D:-Water defrost method
Correct Answer:- Option-A
Question69:-What is the normal drinking water temperature maintained in the
water cooler ?
A:-18 to 22 °C
B:-10 to 12 °C
C:-0 to 2 °C
D:-4 to 6 °C
Correct Answer:- Option-B
Question70:-In which refrigerating machine perishable foods are stored for long
period ?
A:-Water cooler
B:-Visible cooler
C:-Deep freezer
D:-Bottle cooler
Correct Answer:- Option-C

Refrigeration Mechanic Exam Question Paper with Answer Page 8

Question71:-The operation of expanding the inside diameter of a pipe to take in the
outside diameter of another pipe end of same size is known as
A:-Brazing
B:-Flaring
C:-Swaging
D:-Pinching
Correct Answer:- Option-C
Question72:-Which gas is used for leak testing and flushing the refrigeration
systems ?
A:-Oxygen
B:-Hydrogen
C:-Helium
D:-Nitrogen
Correct Answer:- Option-D
Question73:-What is the purpose of providing fins on the tubes of a coil ?
A:-To prevent frost formation
B:-Extended surface for heat transfer
C:-For restricting the air flow
D:-For filtering the air
Correct Answer:- Option-B
Question74:-Which instrument make the use of bourdon tube ?
A:-Thermometer
B:-Multimeter
C:-Barometer
D:-Pressure gauge
Correct Answer:- Option-D
Question75:-The component of Ice candy plant which circulates the brine solution
throughout the brine tank is
A:-Compressor
B:-Condenser
C:-Accumulator
D:-Agitator
Correct Answer:- Option-D
Question76:-Refrigerant used in Ice plants is
A:-R12
B:-R134a
C:-R600a
D:-R717
Correct Answer:- Option-D
Question77:-According to the order of priority, which one of the following
components should be started first in an Ice plant ?
A:-Compressor
B:-Condenser water pump
C:-Agitator motor
D:-Defrost heater
Correct Answer:- Option-C
Question78:-Which psychrometer uses battery operated small fan ?
A:-Sling psychrometer
B:-Aspiring psychrometer
C:-Wall mounted psychrometer
D:-Laboratory psychrometer
Correct Answer:- Option-B
Question79:-Dehumidification of air can be done only if the temperature of cooling
coil is
A:-Below the dry bulb temperature of air
B:-Above the dry bulb temperature of air
C:-Below the dew point temperature of air
D:-Between the dry bulb and wet bulb temperature of air
Correct Answer:- Option-C
Question80:-

Refrigeration Mechanic Exam Question Paper with Answer Page 9

Question81:-The efficiency of HEPA filter is
A:-90%
B:-95%
C:-99.97%
D:-92%
Correct Answer:- Option-C
Question82:-In automobile A/C systems the pistons are operated by
A:-Crank shaft
B:-Connecting Rod
C:-Wobble plate
D:-Electric motor
Correct Answer:- Option-C
Question83:-Defrosting cycle is carried out in
A:-Car Air conditioning systems
B:-Package Air conditioning systems
C:-Split Air conditioning systems
D:-Walk in coolers
Correct Answer:- Option-D
Question84:-Seasonal Fruits and Vegetables are made available round the year by
A:-Ice Plant
B:-Ice candy Refrigeration
C:-Central AC systems
D:-Cold Storage
Correct Answer:- Option-D
Question85:-The psychrometric process in which air is heated without any change
in its specific humidity is known as
A:-Adiabatic saturation
B:-Heating and humidification
C:-Heating and dehumidification
D:-Sensible heating
Correct Answer:- Option-D
Question86:-FCU stands for
A:-Freezer Cabinet Unit
B:-Fan Coil Unit
C:-Freezer Control Unit
D:-Fan Control Unit
Correct Answer:- Option-B
Question87:-Glass wool insulation is avoided in duct because of its
A:-Low strength
B:-Low thermal conductivity
C:-High vapour transmission
D:-Low availability
Correct Answer:- Option-C
Question88:-H.E.P.A. Filter stands for
A:-High Efficiency Particulate Air Filter
B:-High Energy Particle Air Filter
C:-High Emissive Particulate Air Filter
D:-Highly Economic Particle Filter
Correct Answer:- Option-A

Question89:-Magnetic clutch is used in
A:-Walk in Coolers
B:-Package Air Conditioning Systems
C:-Car Air Conditioning Systems
D:-Split Air Conditioning Systems
Correct Answer:- Option-C

Question90:-Insulating materials used for cold storage must have
A:-Low thermal conductivity
B:-High thermal conductivity
C:-High moisture absorption
D:-Heavy weight
Correct Answer:- Option-A

Refrigeration Mechanic Exam Question Paper with Answer Page 10

Question91:-The dry bulb temperature lines in psychrometric chart are
A:-Horizontal and uniformly spaced
B:-Horizontal and non uniformly spaced
C:-Vertical and uniformly spaced
D:-Vertical and non uniformly spaced
Correct Answer:- Option-C

Question92:-Desert Cooler or Evaporative Cooler is an application of which of the
following psychrometric process ?
A:-Heating and humidification
B:-Cooling and dehumidification
C:-Cooling and humidification
D:-Sensible cooling
Correct Answer:- Option-C

Question93:-In a Package A/C, the sensing bulb of thermostat which cycles the
compressor is located at the
A:-Air entry side of the cooling coil
B:-Air exit side of cooling coil
C:-Air entry side of condenser coil
D:-Air exit side of condenser coil
Correct Answer:- Option-A

Question94:-The instrument used to measure total pressure inside the duct is
A:-Hygrometer
B:-Anemometer
C:-Velocimeter
D:-Pitot tube manometer
Correct Answer:- Option-D

Question95:-Air filters are used in
A:-Refrigerators
B:-Ice Plant
C:-Walk in coolers
D:-Air conditioning systems
Correct Answer:- Option-D

Question96:-The excessive dehydration of stored food products inside a cold storage happens if the air inside the cold storage is having
A:-Low relative humidity and high air velocity
B:-High relative humidity and high air velocity
C:-High relative humidity and low air velocity
D:-High relative humidity and low volume
Correct Answer:- Option-A

Question97:-In central air conditioning plants, liquid receiver is located at
A:-Inlet of the compressor
B:-Outlet of condenser
C:-Outlet of compressor
D:-Inlet of condenser
Correct Answer:- Option-B

Question98:-Compressor cut out off by HP cut out in Package AC can be caused due
to
A:-Gas leakage
B:-Low refrigerant charge
C:-Dirty condenser
D:-Compressor grounded
Correct Answer:- Option-C

Question99:-Velocity pressure of air inside a duct is the
A:-Sum of static and total pressure
B:-Sum of dynamic and total pressure
C:-Difference between static and total pressure
D:-Difference between dynamic and total pressure
Correct Answer:- Option-C

Question100:-The lubricant oil used with R134a refrigerant is
A:-Mineral oil
B:-POE oil
C:-PUF oil
D:-VAV oil
Correct Answer:- Option-B

Question 100 Which one of the following should not be followed inside a workshop, as per the general safety rules ?
A:-Do not clean hands in the coolant fluid
B:-A machine in motion can be left as it is, by the worker
C:-Roll up the sleeves tightly above the elbow
D:-Sweep away the metal cuttings
Correct Answer:- Option-B

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Refrigeration Mechanic Exam Question Paper with Answer- 100 Nos