Quiz Questions

Question 1 1 Marks

Which condition is maintained for refrigerant in high side of vapour compression system?

A

Above its critical temperature

B

Below its critical temperature

C

Above its freezing temperature

D

Below its freezing temperature

Question 2 1 Marks

What is the unit of heat in M.K.S system?

A

B.T.U (British thermal unit)

B

K.Cal (Kilo Calorie)

C

KV (Kilo Volt)

D

K.W (Kilo Watt)

Question 3 1 Marks

What is bottom dead centre in reciprocating compressor cylinder?

A

The piston moves up from the point of cylinder

B

The piston stops in cylinder at top

C

The piston moves down from the point of cylinder

D

The piston starts in cylinder at top

Question 4 1 Marks

Which components are connected by metering device in vapour compression cycle?

A

Condenser and evaporator

B

Compressor and condenser

C

Evaporator and suction line

D

Compressor and evaporator

Question 5 1 Marks

What is the barometer reading at sea level in Hg column?

A

760 mm

B

750 mm

C

740 mm

D

730 mm

Question 6 1 Marks

Which thermodynamic process the temperature is kept constant?

A

Isobaric process

B

Isothermal process

C

Constant volume process

D

Constant pressure process

Question 7 1 Marks

What is the purpose of accumulator in a refrigerator?

A

Improves oil circulation

B

Prevents surging of refrigerant

C

Avoids hunting of refrigerant

D

Prevents liquid flood back to compressor

Question 8 1 Marks

Which law is related to the constant PV at constant T?

A

Boyles law

B

Charles s law

C

Pascal s law

D

Renaults law

Question 9 1 Marks

Which two components do the compressor function in vapour absorption system?

A

Generator and absorber

B

Generator and separator

C

Generator and condenser

D

Generator and evaporator

Question 10 1 Marks

Which method is used to connect the swaged joint in copper tubes?

A

TIG welding

B

Silver brazing

C

Lead soldering

D

Fusion welding

Question 11 1 Marks

Which compressor dome handles high pressure and high temperature vapour?

A

Semi hermetic reciprocating compressor

B

Open type reciprocating compressor

C

Hermetic reciprocating compressor

D

Hermetic rotary compressor

Question 12 1 Marks

What is top dead centre in reciprocating compressor cylinder?

A

The piston moves down from the point of cylinder

B

The piston moves up from the point of cylinder

C

The piston stops in cylinder at bottom

D

The piston starts in cylinder at bottom

Question 13 1 Marks

What is the equivalent absolute scale for centigrade?

A

Kelvin

B

Celsius

C

Rankine

D

Fahrenheit

Question 14 1 Marks

What is effect of compression process on refrigerant vapour?

A

Heat the vapour below saturation

B

Cool the vapour above saturation

C

Increase the pressure and temperature

D

Decrease the pressure and temperature

Question 15 1 Marks

What is the physical state of ammonia at condenser inlet in vapour absorption system?

A

Solid

B

Liquid

C

Vapour

D

Semi solid

Question 16 1 Marks

What is the boiling point of pure water in centigrade scale?

A

212 Degree Centigrade

B

100 Degree Centigrade

C

32 Degree Centigrade

D

0 Degree Centigrade

Question 17 1 Marks

How the level of heat in a substance is
expressed?

A

Micron

B

Pressure

C

Humidity

D

Temperature

Question 18 1 Marks

Which components maintain the pressure difference in RAC system?

A

Condenser and filter

B

Evaporator and motor

C

Receiver and condenser

D

Compressor and expansion device

Question 19 1 Marks

What is the absolute pressure of gas in a cylinder, if gauge reads 135.3 p.s.i?

A

130 p.s.i.a

B

140 p.s.i.a

C

150 p.s.i.a

D

160 p.s.i.a

Question 20 1 Marks

Which refrigeration system works on
directly by the heat energy?

A

Jet refrigeration

B

Mechanical refrigeration

C

Vapour absorption refrigeration

D

Vapour compression refrigeration

Question 21 1 Marks

What is the melting temperature of silver
brazing rod?

A

1120 Degree F

B

1200 Degree F

C

1250 Degree F

D

1300 Degree F

Question 22 1 Marks

Which component controls the thermostat and defrost heater in frost free refrigerator?

A

Thermoheater

B

Defrost timer

C

Relay

D

OLP

Question 23 1 Marks

Which instrument is used for measuring
heat?

A

Thermometer

B

Anemometer

C

Calorimeter

D

Ammeter

Question 24 1 Marks

What is the rate of doing work?

A

Duty

B

Force

C

Power

D

Velocity

Question 25 1 Marks

Which factors produce work?

A

Force and distance

B

Time and distance

C

Force and power

D

Force and time

Question 26 1 Marks

What is the temperature set in thermostat that stops the compressor motor?

A

Cut in

B

Range

C

Cut out

D

Differential

Question 27 1 Marks

Which is used to connect the rotor bars in 3phase squirrel cage induction motor?

A

Screw

B

Welded

C

End ring

D

Nut and bolt

Question 28 1 Marks

What is the use of suction baffle in a scroll compressor?

A

Reduce noise of compressor

B

Increase noise of compressor

C

Reduce capacity of compressor

D

Allow liquid to enter into compressor

Question 29 1 Marks

What is the physical condition of refrigerant
in hermetic dome of rotary compressor?

A

LP Liquid

B

HP Liquid

C

HP Vapour

D

LP Vapour

Question 30 1 Marks

What is the formula to find out the
synchronous speed of induction motor?

A

Ns=(150P/f)

B

Ns=(120f/P)

C

Ns=(150f/P)

D

Ns=(120P/f)

Question 31 1 Marks

Which is a positive displacement
compressor?

A

Centrifugal compressor

B

Scroll compressor

C

Water pump

D

Oil pump

Question 32 1 Marks

Which type of compressor is used for domestic refrigerator?

A

Semi sealed compressor

B

Centrifugal compressor

C

Hermetic compressor

D

Open type compressor

Question 33 1 Marks

Which movement of the scroll compresses the low pressure vapour in scroll compressor?

A

Reciprocating

B

Centrifugal

C

Rotating

D

Orbital

Question 34 1 Marks

What is the method of starting a 3 phase slip ring induction motor?

A

With starting relay

B

Using starting capacitor

C

With running capacitor

D

Adding resistance to rotor winding

Question 35 1 Marks

Which gas is used for pressure testing the compressor dome?

A

Air

B

Oxygen

C

Nitrogen

D

Refrigerant

Question 36 1 Marks

Where the refrigerant vapour is compressed in scroll compressor?

A

Fixed and reciprocating scroll

B

Between fixed and orbiting scrolls

C

Crank and connecting rod

D

Eccentric and cylinder

Question 37 1 Marks

Which lubricant oil is used in swash plate of R 134a compressor?

A

Servo 20

B

POE

C

SAE - 40

D

Mineral oil

Question 38 1 Marks

Which part connects the piston with small end of connecting rod in a reciprocating compressor?

A

Piston pin

B

Piston bolt

C

Piston rings

D

Piston sleeve

Question 39 1 Marks

Which motor has the least starting
torque?

A

CSIR

B

CSR

C

RSIR

D

PSC

Question 40 1 Marks

How the difference between the
synchronous speed and the actual rotor speed is
specified?

A

Lead

B

Lag

C

Slip

D

Trip

Question 41 1 Marks

Which capacitor is disconnected by relay in capacitor start and induction run motor?

A

Starting capacitor

B

Running capacitor

C

Boosting capacitor

D

Power factor correction capacitor

Question 42 1 Marks

What is the reason for swash plate compressor failure in car AC?

A

Oil level is low

B

Oil level is medium

C

Thermostat not working

D

Refrigerant charge normal

Question 43 1 Marks

What is the reason for poor compression?

A

Less clearance volume

B

Scratches on the piston surface

C

Lapped valve plate and reed seat

D

Good lubrication on the moving parts

Question 44 1 Marks

What is the effect of moist air present inside the hermetic system?

A

Capacity of compressor will increase

B

Less wear and tear in compressor

C

Harmful to the compressor and motor

D

Increase the life of compressor

Question 45 1 Marks

Which cooling medium is used to cool the motor of a hermetic reciprocating compressor in AC?

A

Discharge vapour

B

Liquid refrigerant

C

Suction vapour

D

Water

Question 46 1 Marks

What is the use of capacitor in PSC
operated induction motor?

A

Decrease the starting torque

B

Cancel the starting torque

C

Improve the power factor

D

Decrease the power factor

Question 47 1 Marks

Which instrument is used to identify the
terminals of a compressor motor?

A

Ammeter

B

Voltmeter

C

Ohm meter

D

Anemometer

Question 48 1 Marks

What is the revolving part of induction motor?

A

Stator

B

Rotor

C

Relay

D

Winding

Question 49 1 Marks

Which is disconnected by centrifugal switch is RSIR motor?

A

Running winding

B

Common winding

C

Starting winding

D

Running capacitor

Question 50 1 Marks

What is the use of a starting capacitor in single phase induction motor?

A

Improve power factor

B

Increase starting torque

C

Decrease starting torque

D

Dis connect starting winding

Question 51 1 Marks

Why frost accumulates in window AC evaporator?

A

Over charge of refrigerant

B

Less charge of refrigerant

C

Capillary chocking

D

Air filter blocked

Question 52 1 Marks

What is the remedy for defective heating element in a frost free refrigerator?

A

Repair heater

B

Readjust the heater

C

Replace heater and bimetal thermo

D

Reuse the heater and over load protector

Question 53 1 Marks

What is the desiccant used in dehydrator of hydrocarbon charged RAC unit?

A

Silica gel

B

Ammonia

C

Sulphur dioxide

D

Calcium chloride

Question 54 1 Marks

Which expansion valve is suitable for constant load operation?

A

King valve

B

Relief valve

C

Low side float valve

D

Automatic expansion valve

Question 55 1 Marks

What is the advantage of using capillary tube as an expansion device?

A

Temperature balancing is easy

B

Pressure balancing is easy

C

Volume balancing is easy

D

Complicate design

Question 56 1 Marks

Why there is no frosting at the bottom only in plate coil evaporator used with refrigerator?

A

Shortage of refrigerant

B

Oil present in the coil

C

Excess of refrigerant

D

Liquid in the coil

Question 57 1 Marks

Which colour is used for painting condenser coil?

A

Green

B

Black

C

Blue

D

Red

Question 58 1 Marks

What is the reason for frost accumulation in
between fins and tubes of evaporator in frost free
refrigerator?

A

Under charge of refrigerant

B

Over charge of refrigerant

C

Defective fan motor

D

Defective timer

Question 59 1 Marks

Which type of expansion device is used in frost free refrigerator?

A

Float valve

B

Capillary tube

C

Automatic expansion valve

D

Thermostatic expansion valve

Question 60 1 Marks

How much minimum gap is left on either side of the refrigerator from the wall during installation?

A

5 cm

B

10 cm

C

15 cm

D

25 cm

Question 61 1 Marks

Which gas is used to flush out the coils of air cooled condenser?

A

Dry nitrogen

B

Pure dry air

C

Oxygen

D

kaksr

Question 62 1 Marks

What is the type of condenser used in direct cool refrigerator?

A

Fin and tube

B

Shell and tube

C

Wire mesh

D

Tube in tube

Question 63 1 Marks

What is the remedy for broken bimetal thermo in a frost free refrigerator?

A

Repair the bimetal thermo

B

Reuse the bimetal thermo

C

Replace the bimetal thermo

D

Readjust the bimetal thermo

Question 64 1 Marks

What is the process of accumulation of ice on the surface of evaporator?

A

Frosting

B

Defrosting

C

Evacuating

D

Melting of frost

Question 65 1 Marks

How pressure drop is achieved in capillary tube of refrigeration cycle?

A

The friction between refrigerant and tube

B

The friction between refrigerant and oil

C

The friction between piston and cylinder

D

The friction between belt and pulley

Question 66 1 Marks

Which type of insulation material is used in modern refrigerators?

A

Saw dust

B

Glass wool

C

Thermocole

D

Poly urethane foam

Question 67 1 Marks

What is the effect of pressure drop at the inlet of the evaporator?

A

Flashing of liquid refrigerant

B

Freezing of liquid refrigerant

C

Freezing of liquid

D

Boiling of oil

Question 68 1 Marks

Which component is connected in series with bimetal thermo in a frost free refrigerator?

A

Blower

B

Door switch

C

Cabinet bulb

D

Defrost heater

Question 69 1 Marks

Which type of condenser is directly placed on water spray and air?

A

Shell and tube condenser

B

Water cooled condenser

C

Evaporative condenser

D

Air cooled condenser

Question 70 1 Marks

Where the dehydrator is installed in a refrigeration system?

A

Discharge line

B

Capillary line

C

Suction line

D

Liquid line

Question 71 1 Marks

Why evaporator of air conditioner has more fins per inch?

A

Increase the air contact

B

Increase the water dripping

C

Decrease the air circulation

D

Produce more ice

Question 72 1 Marks

Which type of drier filter is suitable for HFC refrigerants?

A

Molecular sieve type

B

Activated alumina

C

Activated carbon

D

Silica gel

Question 73 1 Marks

Which application uses the capillary tube expansion device?

A

Domestic RAC units

B

Industrial ice plants

C

Commercial AC plants

D

Hospital IAQ systems

Question 74 1 Marks

What is the physical state of refrigerant at the outlet of condenser in vapour compression cycle?

A

High pressure vapour

B

High pressure liquid

C

Low pressure liquid

D

Low pressure vapour

Question 75 1 Marks

Which evaporator is known as extended surface evaporator?

A

Evaporator tubes

B

Finned evaporator

C

Bare tube evaporator

D

Coiled stake evaporator

Question 76 1 Marks

Which joint is made in either single or multi - strand conductors?

A

Rat tail joint

B

Scarfed joint

C

Britannia joint

D

Western union joint

Question 77 1 Marks

What is the unit of capacitance?

A

Volt

B

Ampere

C

Farad

D

Coulomb

Question 78 1 Marks

Which material is used for making disc in energy meter?

A

Aluminium

B

Copper

C

Brass

D

Zinc

Question 79 1 Marks

What is the load resistance in an electrical circuit, if current, I = 2 amp and supply, V = 10 volt?

A

2 Ohms

B

3 Ohms

C

4 Ohms

D

5 Ohms

Question 80 1 Marks

Which law relates to voltage, current and resistance in an electrical circuit?

A

Ohm s law

B

Lenz s law

C

Newton s law

D

Faraday s law

Question 81 1 Marks

Which winding has more inductance in refrigerator compressor motor?

A

Run

B

Start

C

Common

D

Start and common

Question 82 1 Marks

What is the effect of pouring water on electrodes resistance in earth pit?

A

Decreases

B

Increases

C

Equalises

D

Remains same

Question 83 1 Marks

Which tool is used for skinning the insulation of cables and cleaning the wire surface?

A

Hacksaw

B

Firmer chisel

C

Electrician's knife

D

Combination pliers

Question 84 1 Marks

Which power supply has the fixed polarity?

A

Direct current

B

Signal voltage

C

Signal ripples

D

Alternating current

Question 85 1 Marks

Which winding has low resistance in resistance start induction run motor?

A

Running winding

B

Starting winding

C

Auxiliary winding

D

Common winding

Question 86 1 Marks

Which is the common terminal while Ohm meter reads AB = 10 Ohm, AC = 15 Ohm and BC = 25 Ohm if the motor terminals are A, B and C?

A

Terminal A

B

Terminal B

C

Terminal C

D

Earth Terminal

Question 87 1 Marks

Which type of rotor is used in split phase induction motor?

A

Wound coil

B

Eccentric

C

Squirrel cage

D

Permanent magnet

Question 88 1 Marks

What is the total resistance if two resistors R1 and R2 are connected in series?

A

(R1 - R2) Ohms

B

(R1 + R2) Ohms

C

(R1 x R2) Ohms

D

(R1 / R2) Ohms

Question 89 1 Marks

Which type of conductor is used for bus bars?

A

Solid conductor

B

Thermal conductor

C

Stranded conductor

D

Standard conductor

Question 90 1 Marks

What is the supply voltage if a current of 2 ampere flows through 10 Ohm resistor in a circuit?

A

20 Volt

B

45 Volt

C

55 Volt

D

65 Volt

Question 91 1 Marks

What is the unit of electric current?

A

Ampere

B

Farad

C

Ohm

D

Volt

Question 92 1 Marks

Which property limits the flow of electrons in an electrical circuit?

A

Voltage

B

Current

C

Resistance

D

Conductance

Question 93 1 Marks

What is the maximum capacity of 3 phase squirrel cage induction motor used with direct on line (DOL) starter?

A

5 HP

B

10 HP

C

15 HP

D

20 HP

Question 94 1 Marks

What is the unit of electrical energy?

A

Volt

B

Watt

C

Ampere

D

Kilo watt hour

Question 95 1 Marks

Which type of 1-? motor has high starting torque?

A

Permanent capacitor

B

Resistance start induction run

C

Capacitor start and capacitor run

D

Induction start and induction run

Question 96 1 Marks

Which material is used to avoid oxidation between aluminium conductor and the terminal?

A

Petrol

B

Grease

C

Shellac

D

Kerosene

Question 97 1 Marks

What is the rotor speed with respect to stator field speed in an induction motor?

A

Less than the stator speed

B

More than the stator speed

C

Equal to the stator speed

D

More than the fly wheel

Question 98 1 Marks

How electrons flow in a battery circuit?

A

Phase to earth

B

Phase to neutral

C

Positive to negative polarity

D

Negative polarity to positive polarity

Question 99 1 Marks

What is the condition of compressor motor if Ohm meter reads infinity across common and start terminals?

A

Running winding open

B

Starting winding open

C

Starting winding shorted

D

Running winding shorted

Question 100 1 Marks

Which meter indicates the true power directly in an electrical circuit?

A

Ammeter

B

Ohm meter

C

Watt meter

D

Volt meter

Question 101 1 Marks

Why the temperatures of inlet and outlet water in shell and tube condenser are recorded in log sheet?

A

Study about the plant

B

Judge quality of water

C

Checking the hardness of water

D

Fix descaling time for condenser

Question 102 1 Marks

Which compressor is used only in central AC systems?

A

Scroll

B

Screw

C

Rotary

D

Centrifugal

Question 103 1 Marks

Which valve is used to release the non condensable gases from AC plant?

A

Purge valve

B

Check valve

C

Service valve

D

Solenoid valve

Question 104 1 Marks

Which electronic component senses the temperature in indoor unit of VRV system?

A

Resistor

B

Thyristor

C

Transistor

D

Thermistor

Question 105 1 Marks

What is the purpose of evacuating the system before gas charging?

A

Flush oil particles

B

Charge refrigerant

C

Remove refrigerant

D

Remove moisture and non-condensable

Question 106 1 Marks

Why the LP cut out control is bypassed electrically before pump down operation?

A

Avoid oil foaming

B

Prevent liquid entry to compressor

C

Increase current of the compressor motor

D

To lower the suction pressure close to 0.5 kg/cm2

Question 107 1 Marks

Which refrigerant is used with VRF AC system?

A

R 11

B

R 12

C

R 502

D

R 410A

Question 108 1 Marks

Which valve is used for gas charging and pressure checking in central AC plants?

A

Safety valve

B

Service valve

C

Solenoid valve

D

Non return valve

Question 109 1 Marks

Which process is done to remove the oil and other impurities from the condenser tubes?

A

Purging

B

Flushing

C

Evacuation

D

Pressurising

Question 110 1 Marks

Which version of motors are used in ductless multisplit system?

A

Bioptional drive

B

Trioptional drive

C

Variable frequency drive

D

Constant frequency drive

Question 111 1 Marks

How the indoor unit acts during heating cycle of heat pump?

A

Condenser

B

Evaporator

C

Expansion device

D

Electrical heater

Question 112 1 Marks

Which parameter of power supply reduces the starting current in VFD motor?

A

Decreased power factor

B

Increased supply voltage

C

Lower frequency operation

D

Decreased resistance mode

Question 113 1 Marks

Which valve is first closed to start the pump down operation in central AC plant?

A

Receiver inlet valve

B

Receiver outlet valve

C

Suction service valve

D

Discharge service valve

Question 114 1 Marks

Which parameters in log sheet indicate the air blocking in ducts?

A

All grille temperatures

B

Liquid line temperature

C

Inlet and outlet temperature of chillier

D

Temperatures in chilled water system

Question 115 1 Marks

Which set of components are used in FCU?

A

Air filter, blower, condenser

B

Compressor, fan, condenser

C

Air filter, cooling coil, blower motor

D

Cooling coil, condenser, fan motor

Question 116 1 Marks

What is the expansion of HVAC?

A

Heavy Vehicle Air Conditioning

B

Heating, Vibration, Auto Correction

C

Heating, Ventilation Automatic Control

D

Heating, Ventilation and Air Conditioning

Question 117 1 Marks

What is the cause of oil foaming in compressor crankcase at the time of starting?

A

Poor condensation

B

Damaged oil separator

C

Excess oil in crankcase

D

Defective oil heater/circuit

Question 118 1 Marks

Which type of AC system is capable of heating or cooling in different zones simultaneously?

A

Package AC

B

Central plant AC

C

VRV AC system

D

VAV AC system

Question 119 1 Marks

What is the effect on system performance if the AC system is at undercharged condition?

A

Poor cooling

B

Excess cooling

C

Compressor over loading

D

Compressor trips by HP cut out

Question 120 1 Marks

Which tool is used for descaling the condenser tubes in shell and tube condenser?

A

Steel brush

B

Brass brush

C

Sponge brush

D

Teflon fibre brush

Question 121 1 Marks

What is the benefit of VRV system?

A

Bigger in size

B

Many controls

C

Energy saving

D

Saving refrigerant

Question 122 1 Marks

What is the value of absolute vacuum in millimeters of mercury?

A

-76

B

-760

C

-14.7

D

-10.33

Question 123 1 Marks

What is the benefit of preventive maintenance in AC plant?

A

Reduce water flow

B

Increase running cost

C

Prevent plant s break down

D

Decrease refrigerant charge

Question 124 1 Marks

Which distribution system is absent in VRV operation compared to central AC plant?

A

Refrigeration

B

Ducting system

C

Refrigerant flow

D

Interlocked wiring

Question 125 1 Marks

What is the expansion of PMV used in VRV system?

A

Prime Mover Valve

B

Pass Modulate Valve

C

Phase Modulate Valve

D

Pulse Modulating Valve

Question 126 1 Marks

Which semiconductor material is used to make diodes?

A

Steel

B

Silicon

C

Copper

D

Aluminium

Question 127 1 Marks

Which type of diode is used for communication circuits?

A

Signal diode

B

Zener diode

C

Rectifier diode

D

Switching diode

Question 128 1 Marks

What is the name of electronic
circuit?

A

Bridge rectifier

B

Half wave rectifier

C

Full wave rectifier

D

Quarter wave rectifier

Question 129 1 Marks

Which material is used for making ICs?

A

Silicon

B

Carbon

C

Platinum

D

Mild steel

Question 130 1 Marks

What is the equivalent of one microfarad in farad?

A

10-3 farad

B

10-6 farad

C

10-9 farad

D

10-12 farad

Question 131 1 Marks

Which component is used as a switching device in electronic circuit?

A

SCR

B

Diode

C

Capacitor

D

Zener diode

Question 132 1 Marks

How the ability of a conductor is called if it induces the voltage in the same conductor?

A

Self inductance

B

Conductance

C

Capacitance

D

Resistance

Question 133 1 Marks

Which electronic component is the voltage regulator?

A

Zener diode

B

Transistor

C

Triac

D

Diac

Question 134 1 Marks

Which material is used for making zener diode?

A

Lead

B

Silicon

C

Titanium

D

Platinum

Question 135 1 Marks

Which device maintains a constant DC output?

A

Load regulators

B

Rectifier circuits

C

Current limiters

D

Voltage regulators

Question 136 1 Marks

Which application uses the digital
ICs?

A

Amplifier

B

Logic gates

C

Tuned circuits

D

Voltage regulator

Question 137 1 Marks

What is the name of active component used in electronic circuit?

A

Transistor

B

TRIAC

C

DIAC

D

SCR

Question 138 1 Marks

What are the active components used in electronic circuits?

A

Transformers and inductors

B

Transistors, diodes and SCRs

C

Semi conductors and transformers

D

Resistors, capacitors and inductors

Question 139 1 Marks

What is the reverse break down voltage range of zener diode?

A

0.1 to 0.5 volt

B

0.5 to 1 volt

C

3 to 18 volt

D

1 to 3 volt

Question 140 1 Marks

What are the passive components used in
electronic circuits?

A

Resistors, capacitors and inductors

B

Transformers and semiconductors

C

Semi conductors and transistors

D

Transistors, diodes and SCRs

Question 141 1 Marks

Which tool is used for bending, seaming and forming of sheet metal?

A

Bench vice

B

Hand vice

C

Stakes

D

Shear

Question 142 1 Marks

Which part of tube cutter is used for removing the burrs from copper tubes?

A

Roller

B

Cutter

C

Reamer

D

Bender

Question 143 1 Marks

What is the material composition of a Tin man s solder?

A

50% Tin 50% Zinc

B

50% Tin 50% lead

C

50% Zinc 50% lead

D

50% Tin 50% Bronze

Question 144 1 Marks

What is the least count of a metric micrometer?

A

0.1 mm

B

0.01 mm

C

0.001 mm

D

000.1 mm

Question 145 1 Marks

Which extinguishes the fire on electrical equipment?

A

Oil

B

Foam

C

Water

D

Halon

Question 146 1 Marks

Which tool is used for trimming the edges of a sheet metal cylinder?

A

Straight snips

B

Bent snips

C

Tube cutter

D

Scissors

Question 147 1 Marks

What is the angle of the tip of centre punch?

A

30 Degree

B

60 Degree

C

90 Degree

D

120 Degree

Question 148 1 Marks

Which tool is used for bending long sheet metal?

A

Folding bar

B

Bench vice

C

Hand vice

D

Shear

Question 149 1 Marks

Which is the point angle of a twist drill used for zinc alloy?

A

90 Degree

B

100 Degree

C

118 Degree

D

125 Degree

Question 150 1 Marks

What is the name of the caliper having one leg with an adjustable divider point and other leg is bent?

A

Jenny Caliper

B

Inside Caliper

C

Outside caliper

D

Spring joint caliper

Question 151 1 Marks

Which materials are used to make mallets?

A

Wood, cast iron

B

Wood, rubber

C

Rubber, brass

D

Wood, brass

Question 152 1 Marks

Which material is used to clean oil and grease on the floor?

A

Cotton waste

B

Saw dust

C

Water

D

Air

Question 153 1 Marks

Which file is used for filing wood?

A

Double cut file

B

Single cut file

C

Rasp cut file

D

Smooth file

Question 154 1 Marks

Which instrument is used to measure pressure on both high and low side of the system?

A

Pipe manifold

B

Gauge manifold

C

Pressure manifold

D

Instrument manifold

Question 155 1 Marks

Which tool is used for tightening the odd size bolts and nuts?

A

Socket set

B

Nose pliers

C

Ring spanner

D

Adjustable spanner

Question 156 1 Marks

Which component is used in frost free refrigerator?

A

Plate coil evaporator

B

Liquid receiver

C

Oil separator

D

Timer switch

Question 157 1 Marks

What is the cut out temperature of bimetal thermo in frost free refrigerator?

A

5 Degree Centigrade

B

10 Degree Centigrade

C

20 Degree Centigrade

D

25 Degree Centigrade

Question 158 1 Marks

What is the working condition of component during defrost cycle in frost free refrigerator?

A

Evaporator fan motor is running

B

Compressor is not running

C

Thermostat cuts off

D

Relay activated

Question 159 1 Marks

What is the cause for refrigerator door gap at closing position?

A

Uneven floor level

B

Either side gap more

C

Either side gap less

D

Uneven condenser level

Question 160 1 Marks

What is the advantage of sealed system compared to open type system?

A

Mechanical efficiency is greater

B

Cylinder lubrication is easier

C

Any refrigerant can be used

D

No shaft seal is required

Question 161 1 Marks

Which movement of plunger energises the start winding in relay operation?

A

Vertically up

B

Bottom side

C

Vertically down

D

Horizontally left

Question 162 1 Marks

Which sheet is used to check the tigtness of door gasket of a refrigerator?

A

Rubber

B

Plastic

C

Copper

D

Zinc

Question 163 1 Marks

Which electrical control cuts off heating element in frost free refrigerator?

A

Bimetal thermo

B

Thermostat

C

Relay

D

Timer

Question 164 1 Marks

Which domestic system uses automatic defrost?

A

Frost free refrigerator

B

Conventional refrigerator

C

Split air - conditioner

D

Window air - conditioner

Question 165 1 Marks

Which type of evaporator is used in frost free refrigerator?

A

Plate type

B

Wire mesh

C

Finned tube

D

Shell and tube

Question 166 1 Marks

Where the thermal bulb is fixed in frost free refrigerator?

A

Liquid line

B

Discharge line

C

Last coil of condenser

D

Last coil of evaporator

Question 167 1 Marks

Which device equalizes the system pressure in frost free refrigerator?

A

Capillary tube

B

Compressor

C

Condenser

D

Evaporator

Question 168 1 Marks

Which component switches ON/OFF the starting winding in RSIR motor?

A

Thermostat

B

Capacitor

C

Relay

D

OLP

Question 169 1 Marks

Which device protects the compressor motor from drawing more current?

A

OLP

B

Relay

C

Thermostat

D

Door switch

Question 170 1 Marks

Which is used to clean the condenser fins of a refrigerator?

A

Painting brush

B

Diluted acid

C

Soap solution

D

Fin comb

Question 171 1 Marks

Which component is replaced to prevent air entering the refrigerator cabinet?

A

Thermostat

B

Door gasket

C

Door paint

D

Door hinges

Question 172 1 Marks

What is the temperature maintained in the refrigerator freezer?

A

0 Degree Centigrade

B

- 15 Degree Centigrade

C

- 45 Degree Centigrade

D

- 65 Degree Centigrade

Question 173 1 Marks

Which method of refrigeration system is adopted in frost free refrigerator?

A

Vapour compression

B

Vapour absorption

C

Water vapour

D

Evacuating

Question 174 1 Marks

What is the reason if refrigerator runs normally but no cooling effect?

A

Leakage of refrigerant

B

Condenser block

C

Filter block

D

Over charge

Question 175 1 Marks

Which component is turned off while defrost heater is energised?

A

Cabinet bulb

B

Evaporator fan

C

Thermostat sensor

D

Over load protector

Question 176 1 Marks

How the capacity of refrigerator is expressed?

A

Weightage

B

Tonnage

C

Wattage

D

Litres

Question 177 1 Marks

Why frost free model refrigerator takes less freezing time of products?

A

Forced air circulation

B

Natural air circulation

C

Low temperature setting

D

High temperature setting

Question 178 1 Marks

What is the effect of bimetal thermo stucks in ON position in frost free refrigerator?

A

Accumulation of frost

B

More cooling

C

Poor cooling

D

No cooling

Question 179 1 Marks

Where the manually defrosted water is stored in refrigerator?

A

Tray on top of the compressor

B

Bottom of the evaporator

C

Bottom of the condenser

D

Top of the freezer

Question 180 1 Marks

Which component defrosts in frost free refrigerator?

A

Bulb

B

Heater

C

Thermostat

D

Capillary tube

Question 181 1 Marks

Which bearing is used in condenser motor of outdoor unit in ductable multi split air conditioner?

A

Open ball bearing

B

Thrust bearing

C

Sleeve bearing

D

Ball bearing

Question 182 1 Marks

Why CFC 12 system is replaced by HFC 134a system in car AC?

A

Increase ODP

B

Increase GWP

C

GWP becomes zero

D

ODP becomes zero

Question 183 1 Marks

Which valve helps to attend mechanical faults without wasting the gas in split AC?

A

Gate valve

B

Float valve

C

Service valve

D

Expansion valve

Question 184 1 Marks

Which process is done first in split AC for shifting from one place to another?

A

Flushing

B

Evacuation

C

Pump down

D

Vacuumisation

Question 185 1 Marks

What is the effect on defective thermostat sensor in split AC?

A

Unit consumes less power

B

Increases super heat

C

AC unit runs continuously

D

Relay malfunctions

Question 186 1 Marks

Which material is used to make ducts in split AC?

A

Thermocole

B

GI sheet

C

Wood

D

Fibre

Question 187 1 Marks

Which component belongs to indoor unit of split AC?

A

Compressor

B

Condenser

C

Evaporator

D

Drier

Question 188 1 Marks

Which type of fan blade is used with indoor unit?

A

Guide vane

B

Blower

C

Axial

D

Vane|

Question 189 1 Marks

Which fan is used in condensing unit of ductable split air conditioner?

A

Forward curved fan

B

Centrifugal fan

C

Propeller fan

D

Radial fan

Question 190 1 Marks

Which motor is used to drive the condenser fan of out-door unit in ductable split air conditioner?

A

Capacitor start capacitor run motor

B

Three phase induction motor

C

Permanent split motor (PSC)

D

Shaded pole motor

Question 191 1 Marks

Which device switches ON/OFF the car AC compressor?

A

Crank shaft

B

Blower unit

C

Rotor winding

D

Magnetic clutch

Question 192 1 Marks

Which device equalizes the pressure between low and high side of split AC during ?OFF? cycle?

A

Suction tube

B

Copper tube

C

Capillary tube

D

Discharge tube

Question 193 1 Marks

What is the use of magnetic clutch in Car AC?

A

Indicate liquid level in the compressor

B

Indicate oil level in the compressor

C

Control ON/OFF for compressor

D

Add oil in the system

Question 194 1 Marks

How long the filter drier unit is used in car AC?

A

1 year

B

2 years

C

3 years

D

4 years

Question 195 1 Marks

Why the idler pulley is used in belt driven car AC?

A

Decrease the belt vibration

B

Increase the belt tension

C

Increase the feathering

D

Decrease the belt tension

Question 196 1 Marks

How many fan motors are used in split AC?

A

Two

B

Five

C

Four

D

Three

Question 197 1 Marks

Where the refrigerant is stored in split AC during pump down operation?

A

Accumulator

B

Compressor

C

Evaporator

D

Condenser

Question 198 1 Marks

Which speed is recommended for checking optimum performance in car AC?

A

1600 rpm

B

2600 rpm

C

3600 rpm

D

4600 rpm

Question 199 1 Marks

What is the reason for poor cooling effect in multi split air conditioner?

A

Efficient compressor

B

Proper condensation

C

Good insulation

D

Dirty air filter

Question 200 1 Marks

What is the reason for sweating of water on drier filter?

A

Air filter blocked

B

Partially chocked drier filter

C

More air flows through the evaporator

D

Dust accumulated on condenser

Question 201 1 Marks

Which control switch is connected in series with magnetic clutch in Car AC wiring?

A

Piston pin

B

Thermostat control

C

Automatic expansion valve

D

Thermostatic expansion valve

Question 202 1 Marks

What type of material is used to support the tubes on both sides of air cooled condenser?

A

Copper sheets

B

Mild steel sheet

C

Aluminium sheets

D

Galvanised iron sheets

Question 203 1 Marks

What is the reason for no cooling effect in car AC?

A

Air in the system

B

Excess of refrigerant

C

Refrigerant leaked

D

Moisture in the system

Question 204 1 Marks

Where the filter drier is installed in a car AC system?

A

Liquid line

B

Suction line

C

Service line

D

Discharge line

Question 205 1 Marks

Which causes the clogged orifice in TEV of car AC system?

A

Nitrogen

B

Oxygen

C

Moisture

D

Non condensable gases

Question 206 1 Marks

Which refrigerant is used in vapour compression cycle?

A

Secondary refrigerant

B

Primary refrigerant

C

Brine solution

D

Water

Question 207 1 Marks

Which insulating material is poured as liquid?

A

Glass Wool

B

Cork Board

C

Wood Shave

D

Poly Urethane Foam (PUF)

Question 208 1 Marks

What is the category of R 502 refrigerant?

A

Azeotropes

B

Halocarbon

C

Hydrocarbon

D

Organic compounds

Question 209 1 Marks

What is the advantage of universal colour coding of refrigerant cylinders?

A

Easy to identify

B

Make good appearance

C

Prevent corrosion on cylinder

D

Provide extra strength to cylinder

Question 210 1 Marks

What is the category of R 290 refrigerant?

A

Halocarbons

B

Azeotropes

C

Hydrocarbons

D

Organic compounds

Question 211 1 Marks

What is the desirable property of POE lubricant?

A

Hygroscopic

B

Miscible with HFCs

C

Forms acid with moisture

D

Toxic gas produced during brazing

Question 212 1 Marks

Which refrigerant is inactive to ozone layer?

A

R 12

B

R 13

C

R 22

D

R 134a

Question 213 1 Marks

Which is the effective method for refrigerant recovery?

A

Condensing unit

B

Charge migration

C

Push pull recovery

D

Use of system's compressor

Question 214 1 Marks

How much is the maximum capacity of refrigerant to be filled in a returnable service cylinder?

A

Up to 95%

B

Up to 90%

C

Up to 85%

D

Up to 80%

Question 215 1 Marks

Which type of insulating material is used for making ice box to cool beverages?

A

Tar felt

B

Glass wool

C

Fibre glass

D

Thermocole

Question 216 1 Marks

Which is the numerical designation of ammonia refrigerant?

A

700 + ( Molecular mass of NH3) = 717

B

700 + (Molecular mass of NH3) = 718

C

700 + (Molecular mass of NH3) = 719

D

700 + (Molecular mass of NH 3) = 720

Question 217 1 Marks

What type of heat is absorbed by primary refrigerant?

A

Total heat

B

Latent heat

C

Specific heat

D

Sensible heat

Question 218 1 Marks

What is the cylinder colour code of R 22 refrigerant?

A

White

B

Green

C

Orchid

D

Orange

Question 219 1 Marks

What is the category of R 407c refrigerant?

A

Azeotropes

B

Zeotropes

C

Inorganic

D

Organic

Question 220 1 Marks

Why universal numbering system is adopted for different refrigerants?

A

Identifying the refrigerant's names

B

Mixing the lubricant combination

C

Fixing the drier combination

D

Identify the systems

Question 221 1 Marks

Which gas is universally taken as the basic reference for GWP?

A

SO2

B

CO2

C

NH3

D

AIR

Question 222 1 Marks

How the refrigerants are classified based on heat absorption by latent and sensible heat?

A

Primary and secondary

B

Organic and inorganic

C

Zeotropic and azeotropic

D

Halocarbons and hydrocarbons

Question 223 1 Marks

Where does the ozone layer exist in atmosphere?

A

Mesosphere

B

Stratosphere

C

Ionosphere

D

Exosphere

Question 224 1 Marks

How to safe guard the hands while handling glass wool?

A

Wearing goggles

B

Wearing gloves

C

Using mask

D

Using shoes

Question 225 1 Marks

Which position is safe for storing refrigerant cylinder?

A

Upside down

B

Horizontal

C

Inclined

D

Upright

Question 226 1 Marks

What is the ozone depleting potential of R 134a Refrigerant?

A

0

B

1

C

2

D

3

Question 227 1 Marks

What is the name of process that changes the used refrigerant to new product?

A

Recover

B

Recycle

C

Reclaim

D

Manufacture

Question 228 1 Marks

How numerical designations of inorganic refrigerants are assigned?

A

Divide 700 to molecular mass of compound

B

Multiply 700 to molecular mass of compound

C

Adding 700 to molecular mass of compound

D

Subtracting 700 from molecular mass of compound

Question 229 1 Marks

Which is the green house gas?

A

Oxygen of atmospheric air

B

Chlorofluoro carbon in air

C

Helium of atmospheric air

D

Neon of atmospheric air

Question 230 1 Marks

Which property is desirable for an ideal refrigerant?

A

High boiling point

B

High freezing point

C

High specify volume

D

High latent heat value

Question 231 1 Marks

What is the purpose of relay used in window air conditioner?

A

Disconnect the starting capacitor

B

Disconnect the running capacitor

C

Disconnect the fan capacitor

D

Disconnect the winding

Question 232 1 Marks

Which is increased by the fins of condenser tubes in window air conditioner?

A

Heat transfer rate

B

Power consumption

C

Discharge pressure

D

Refrigerant flow rate

Question 233 1 Marks

What is the reason for the compressor motor burn out in a window air conditioner?

A

Defective fan capacitor

B

Defective fan motor

C

Defective blower

D

Defective OLP

Question 234 1 Marks

Which type of compressor is used in window air conditioner?

A

Belt drive

B

Open type

C

Sealed type

D

Swash plate

Question 235 1 Marks

What is the remedy to remove moisture from the window AC system?

A

Over gas charge in the system

B

Evacuate the system deeply

C

Clean the evaporator fins

D

Clean the condenser fins

Question 236 1 Marks

Which safety device is used for compressor motor in window air conditioner?

A

Relay

B

Starting capacitor

C

Running capacitor

D

Over load protector

Question 237 1 Marks

What is the cooling capacity of 0.5 TR in BTU / hr?

A

6000

B

12000

C

18000

D

24000

Question 238 1 Marks

1 Which control device is used to maintain the room air temperature?

A

OLP

B

Relay

C

Thermostat

D

Selector switch

Question 239 1 Marks

What is the purpose of operating the fan motor first and then the compressor motor in Air conditioners?

A

Cool the coils first by fan

B

Cool the compressor by fan

C

Minimise the noise of motors

D

Stop the high starting current by both motors

Question 240 1 Marks

What is the cause of reduced supply air throw though air filter is clean in window AC?

A

No frost in the evaporator

B

Frost accumulated in the evaporator

C

Dust accumulated in the condenser

D

No dust accumulated in the evaporator

Question 241 1 Marks

Which is indicated by the arrow mark on filter drier component?

A

Flow direction of air

B

Position of capillary tube

C

Flow direction of refrigerant

D

Arrangement of desiccant and filter

Question 242 1 Marks

What is the reason for Very high condenser temperature in a window air conditioner?

A

Water splashes condenser

B

More air flows into the condenser

C

Fan motor working in good condition

D

Dust accumulated in the condenser fins

Question 243 1 Marks

What is the area of room cooled by 1ton window air conditioner?

A

5000 sq.ft

B

2000 sq.ft

C

1000 sq.ft

D

3000 sq.ft

Question 244 1 Marks

Which stabilizer capacity is used for 1 Ton window air conditioner?

A

2 KVA

B

3 KVA

C

4 KVA

D

5 KVA

Question 245 1 Marks

What is the cooling capacity of 1 TR in K Cal / hr?

A

3000

B

4000

C

5000

D

6000

Question 246 1 Marks

Which relay is used in capacitor start, capacitor run (CSR) compressor motor?

A

Voltage relay

B

Current relay

C

Thermal relay

D

Amperage relay

Question 247 1 Marks

What is the reason for excessive frost on evaporator coil in window AC?

A

Evaporator fins not blocked by dust

B

Blower rotating at higher speed

C

Air filter blocked completely

D

More air circulation in evaporator

Question 248 1 Marks

What is the reason for Compressor does not start ?

A

Defective fresh air damper

B

Defective oscillation motor

C

Defective fan motor

D

Defective OLP

Question 249 1 Marks

Which type of evaporator is used in window air conditioner?

A

Bare tube

B

Plate and tube

C

Fins and plate

D

Fins and tube

Question 250 1 Marks

What is the effect of sensing higher
temperature by thermistor NTC?

A

Resistance increases

B

Resistance decreases

C

Resistance becomes zero

D

Resistance becomes infinity

Which condition is maintained for refrigerant in high side of vapour compression system?

What is the unit of heat in M.K.S system?

What is bottom dead centre in reciprocating compressor cylinder?

Which components are connected by metering device in vapour compression cycle?

What is the barometer reading at sea level in Hg column?

Which thermodynamic process the temperature is kept constant?

What is the purpose of accumulator in a refrigerator?

Which law is related to the constant PV at constant T?

Which two components do the compressor function in vapour absorption system?

Which method is used to connect the swaged joint in copper tubes?

Which compressor dome handles high pressure and high temperature vapour?

What is top dead centre in reciprocating compressor cylinder?

What is the equivalent absolute scale for centigrade?

What is effect of compression process on refrigerant vapour?

What is the physical state of ammonia at condenser inlet in vapour absorption system?

What is the boiling point of pure water in centigrade scale?

How the level of heat in a substance is expressed?

Which components maintain the pressure difference in RAC system?

What is the absolute pressure of gas in a cylinder, if gauge reads 135.3 p.s.i?

Which refrigeration system works on directly by the heat energy?

What is the melting temperature of silver brazing rod?

Which component controls the thermostat and defrost heater in frost free refrigerator?

Which instrument is used for measuring heat?

What is the rate of doing work?

Which factors produce work?

What is the temperature set in thermostat that stops the compressor motor?

Which is used to connect the rotor bars in 3phase squirrel cage induction motor?

What is the use of suction baffle in a scroll compressor?

What is the physical condition of refrigerant in hermetic dome of rotary compressor?

What is the formula to find out the synchronous speed of induction motor?

Which is a positive displacement compressor?

Which type of compressor is used for domestic refrigerator?

Which movement of the scroll compresses the low pressure vapour in scroll compressor?

What is the method of starting a 3 phase slip ring induction motor?

Which gas is used for pressure testing the compressor dome?

Where the refrigerant vapour is compressed in scroll compressor?

Which lubricant oil is used in swash plate of R 134a compressor?

Which part connects the piston with small end of connecting rod in a reciprocating compressor?

Which motor has the least starting torque?

How the difference between the synchronous speed and the actual rotor speed is specified?

Which capacitor is disconnected by relay in capacitor start and induction run motor?

What is the reason for swash plate compressor failure in car AC?

What is the reason for poor compression?

What is the effect of moist air present inside the hermetic system?

Which cooling medium is used to cool the motor of a hermetic reciprocating compressor in AC?

What is the use of capacitor in PSC operated induction motor?

Which instrument is used to identify the terminals of a compressor motor?

What is the revolving part of induction motor?

Which is disconnected by centrifugal switch is RSIR motor?

What is the use of a starting capacitor in single phase induction motor?

Why frost accumulates in window AC evaporator?

What is the remedy for defective heating element in a frost free refrigerator?

What is the desiccant used in dehydrator of hydrocarbon charged RAC unit?

Which expansion valve is suitable for constant load operation?

What is the advantage of using capillary tube as an expansion device?

Why there is no frosting at the bottom only in plate coil evaporator used with refrigerator?

Which colour is used for painting condenser coil?

What is the reason for frost accumulation in between fins and tubes of evaporator in frost free refrigerator?

Which type of expansion device is used in frost free refrigerator?

How much minimum gap is left on either side of the refrigerator from the wall during installation?

Which gas is used to flush out the coils of air cooled condenser?

What is the type of condenser used in direct cool refrigerator?

What is the remedy for broken bimetal thermo in a frost free refrigerator?

What is the process of accumulation of ice on the surface of evaporator?

How pressure drop is achieved in capillary tube of refrigeration cycle?

Which type of insulation material is used in modern refrigerators?

What is the effect of pressure drop at the inlet of the evaporator?

Which component is connected in series with bimetal thermo in a frost free refrigerator?

Which type of condenser is directly placed on water spray and air?

Where the dehydrator is installed in a refrigeration system?

Why evaporator of air conditioner has more fins per inch?

Which type of drier filter is suitable for HFC refrigerants?

Which application uses the capillary tube expansion device?

What is the physical state of refrigerant at the outlet of condenser in vapour compression cycle?

Which evaporator is known as extended surface evaporator?

Which joint is made in either single or multi - strand conductors?

What is the unit of capacitance?

Which material is used for making disc in energy meter?

What is the load resistance in an electrical circuit, if current, I = 2 amp and supply, V = 10 volt?

How the level of heat in a substance is
expressed?

Which refrigeration system works on
directly by the heat energy?

What is the melting temperature of silver
brazing rod?

Which instrument is used for measuring
heat?

What is the physical condition of refrigerant
in hermetic dome of rotary compressor?

What is the formula to find out the
synchronous speed of induction motor?

Which is a positive displacement
compressor?

Which motor has the least starting
torque?

How the difference between the
synchronous speed and the actual rotor speed is
specified?

What is the use of capacitor in PSC
operated induction motor?

Which instrument is used to identify the
terminals of a compressor motor?

What is the reason for frost accumulation in
between fins and tubes of evaporator in frost free
refrigerator?

What is the name of electronic
circuit?

Which application uses the digital
ICs?

What are the passive components used in
electronic circuits?