Quiz Questions

Question 1 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 2 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 3 1 Marks

What is the atmospheric pressure at sea
level?

A

1.033 kg/cm2

B

1.3 Kg/cm2

C

1.5 Kg/cm2

D

1.6 Kg/cm2

Question 4 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 5 1 Marks

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

A

Thermoheater

B

Defrost timer

C

Relay

D

OLP

Question 6 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 7 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 8 1 Marks

Which instrument is used for measuring
heat?

A

Thermometer

B

Anemometer

C

Calorimeter

D

Ammeter

Question 9 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 10 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 11 1 Marks

How the level of heat in a substance is
expressed?

A

Micron

B

Pressure

C

Humidity

D

Temperature

Question 12 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 13 1 Marks

What is the capacity of doing work?

A

Work

B

Power

C

Force

D

Energy

Question 14 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 15 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 16 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 17 1 Marks

Which instrument is used to measure atmospheric pressure?

A

Hygrometer

B

Hydrometer

C

Manometer

D

Barometer

Question 18 1 Marks

What is the energy of a body by virtue of its position?

A

Wind energy

B

Kinetic energy

C

Potential energy

D

Electrical energy

Question 19 1 Marks

What is the rate of doing work?

A

Duty

B

Force

C

Power

D

Velocity

Question 20 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 21 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 22 1 Marks

What is the absolute zero temperature in
degree centigrade?

A

0 Degree Centigrade

B

100 Degree Centigrade

C

-273 Degree Centigrade

D

212 Degree Centigrade

Question 23 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 24 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 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

Which is disconnected by centrifugal switch is RSIR motor?

A

Running winding

B

Common winding

C

Starting winding

D

Running capacitor

Question 27 1 Marks

What is the cause for frequent tripping of circuit breaker while starting a single phase motor?

A

Winding open

B

Winding short

C

Motor belt removed

D

No load on the motor

Question 28 1 Marks

Which is a positive displacement
compressor?

A

Centrifugal compressor

B

Scroll compressor

C

Water pump

D

Oil pump

Question 29 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 30 1 Marks

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

A

Reciprocating

B

Centrifugal

C

Rotating

D

Orbital

Question 31 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 32 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 33 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 34 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 35 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 36 1 Marks

Which valve is closed during compression stroke in reciprocating compressor?

A

Service valve

B

Liquid line valve

C

Discharge valve

D

Suction valve

Question 37 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 38 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 39 1 Marks

What is the advantage of a hermetically sealed compressor in refrigerator?

A

Silent operation

B

Easily serviceable

C

Noise is more

D

Cost is high

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

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 42 1 Marks

Which type of rotor is used in 3 Phase induction motor?

A

Squirrel cage rotor

B

Shaded pole rotor

C

Laminated rotor

D

Solid rotor

Question 43 1 Marks

Which motor has the least starting
torque?

A

CSIR

B

CSR

C

RSIR

D

PSC

Question 44 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 45 1 Marks

Which gas is used for pressure testing the compressor dome?

A

Air

B

Oxygen

C

Nitrogen

D

Refrigerant

Question 46 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 47 1 Marks

Which winding is made of thick wire in single phase induction motor?

A

Starting

B

Running

C

Auxiliary

D

Additional

Question 48 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 49 1 Marks

Why the top of dome is hot in a scroll compressor?

A

Discharge plenum is at top

B

Suction super heat is less

C

Suction gas not cooled

D

Undercharged system

Question 50 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 51 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 52 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 53 1 Marks

Which winding has more inductance in refrigerator compressor motor?

A

Run

B

Start

C

Common

D

Start and common

Question 54 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 55 1 Marks

Which power supply has the fixed polarity?

A

Direct current

B

Signal voltage

C

Signal ripples

D

Alternating current

Question 56 1 Marks

Which type of conductor is used for bus bars?

A

Solid conductor

B

Thermal conductor

C

Stranded conductor

D

Standard conductor

Question 57 1 Marks

What is the unit of electric current?

A

Ampere

B

Farad

C

Ohm

D

Volt

Question 58 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 59 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 60 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 61 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 62 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 63 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 64 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 65 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 66 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 67 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 68 1 Marks

What is the unit of electrical energy?

A

Volt

B

Watt

C

Ampere

D

Kilo watt hour

Question 69 1 Marks

What is the unit of capacitance?

A

Volt

B

Ampere

C

Farad

D

Coulomb

Question 70 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 71 1 Marks

Which material is used for making disc in energy meter?

A

Aluminium

B

Copper

C

Brass

D

Zinc

Question 72 1 Marks

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

A

Voltage

B

Current

C

Resistance

D

Conductance

Question 73 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 74 1 Marks

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

A

Petrol

B

Grease

C

Shellac

D

Kerosene

Question 75 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 76 1 Marks

How many terminals are there in a Silicon Controlled Rectifier (SCR)?

A

One

B

Two

C

Four

D

Three

Question 77 1 Marks

How the maximum reverse voltage across the diode is termed in reverse biased condition?

A

Diode voltage

B

Ripple frequency

C

Peak inverse voltage

D

Peak rectification voltage

Question 78 1 Marks

How many diodes are required for making a
bridge rectifier circuit?

A

One

B

Two

C

Four

D

Three

Question 79 1 Marks

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

A

SCR

B

Diode

C

Capacitor

D

Zener diode

Question 80 1 Marks

Which material is used for making ICs?

A

Silicon

B

Carbon

C

Platinum

D

Mild steel

Question 81 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 82 1 Marks

Which type of diode is used for communication circuits?

A

Signal diode

B

Zener diode

C

Rectifier diode

D

Switching diode

Question 83 1 Marks

Which device maintains a constant DC output?

A

Load regulators

B

Rectifier circuits

C

Current limiters

D

Voltage regulators

Question 84 1 Marks

Which application uses the digital
ICs?

A

Amplifier

B

Logic gates

C

Tuned circuits

D

Voltage regulator

Question 85 1 Marks

Which material is used for making zener diode?

A

Lead

B

Silicon

C

Titanium

D

Platinum

Question 86 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 87 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 88 1 Marks

Which electronic component is the voltage regulator?

A

Zener diode

B

Transistor

C

Triac

D

Diac

Question 89 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 90 1 Marks

What is the process involved for converting AC to DC power supply?

A

Inversion

B

Regulation

C

Convection

D

Rectification

Question 91 1 Marks

What is the equivalent of one micron in millimeter?

A

0.0001 mm

B

0.001 mm

C

0.01 mm

D

0.1 mm

Question 92 1 Marks

What is starving in extinguishing the fire?

A

Adding fuel

B

Removal of fuel

C

Clearing the hazards

D

Stop the supply of oxygen

Question 93 1 Marks

Which medium is used to extinguish Class - A fire?

A

CO2

B

Foam

C

Water

D

Dry powder

Question 94 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 95 1 Marks

Which extinguishes the fire on electrical equipment?

A

Oil

B

Foam

C

Water

D

Halon

Question 96 1 Marks

Which tool is used for bending long sheet metal?

A

Folding bar

B

Bench vice

C

Hand vice

D

Shear

Question 97 1 Marks

Which metal is alloyed with zinc to make brass?

A

Iron

B

Copper

C

Bronze

D

Aluminium

Question 98 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 99 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 100 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 101 1 Marks

What is smothering in fire extinguishing?

A

Pouring of CTC

B

Flashing with dry powder

C

Use water to lower temperature

D

Cutting off oxygen supply to fire

Question 102 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 103 1 Marks

Which extinguishes the fire of flammable liquids?

A

Water

B

Air

C

CO2

D

Oil

Question 104 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 105 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 106 1 Marks

What is the result if discharge reed is broken in open type compressor?

A

Poor pumping

B

More pumping

C

Oil pumping

D

No pumping

Question 107 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 108 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 109 1 Marks

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

A

Bimetal thermo

B

Thermostat

C

Relay

D

Timer

Question 110 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 111 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 112 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 113 1 Marks

What is the effect of contamination in refrigeration system?

A

High heating

B

Poor cooling

C

Low pressure

D

Low humidity

Question 114 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 115 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 116 1 Marks

Which device equalizes the system pressure in frost free refrigerator?

A

Capillary tube

B

Compressor

C

Condenser

D

Evaporator

Question 117 1 Marks

Which component is used in frost free refrigerator?

A

Plate coil evaporator

B

Liquid receiver

C

Oil separator

D

Timer switch

Question 118 1 Marks

Which domestic system uses automatic defrost?

A

Frost free refrigerator

B

Conventional refrigerator

C

Split air - conditioner

D

Window air - conditioner

Question 119 1 Marks

How the capacity of refrigerator is expressed?

A

Weightage

B

Tonnage

C

Wattage

D

Litres

Question 120 1 Marks

Which is connected in series with start capacior in motor circuit?

A

Starting winding

B

Common terminal

C

Running Terminal

D

Running winding

Question 121 1 Marks

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

A

Thermostat

B

Capacitor

C

Relay

D

OLP

Question 122 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 123 1 Marks

Which device protects the compressor motor from drawing more current?

A

OLP

B

Relay

C

Thermostat

D

Door switch

Question 124 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 125 1 Marks

Which component defrosts in frost free refrigerator?

A

Bulb

B

Heater

C

Thermostat

D

Capillary tube

Question 126 1 Marks

Which component actuates the defrost cycle in frost free refrigerator?

A

Bimetal thermo

B

Defrost heater

C

Timer

D

Relay

Question 127 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 128 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 129 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 130 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 131 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 132 1 Marks

Which position is safe for storing refrigerant cylinder?

A

Upside down

B

Horizontal

C

Inclined

D

Upright

Question 133 1 Marks

Which is the inorganic refrigerant?

A

R 170

B

R 500

C

R 630

D

R 717

Question 134 1 Marks

What is the effect of releasing HCFC refrigerants to atmosphere?

A

Increases ODP and GWP

B

Decreases GWP and ODP

C

Decreases TEWI

D

Inactive to TEWI

Question 135 1 Marks

Which refrigerant is used in vapour compression cycle?

A

Secondary refrigerant

B

Primary refrigerant

C

Brine solution

D

Water

Question 136 1 Marks

How many hydrogen atoms are present in R 134a?

A

One

B

Two

C

Four

D

Three

Question 137 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 138 1 Marks

What is the category of R 290 refrigerant?

A

Halocarbons

B

Azeotropes

C

Hydrocarbons

D

Organic compounds

Question 139 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 140 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 141 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 142 1 Marks

What is the effect of releasing HFC refrigerants to the atmosphere?

A

Increase global warming potential

B

Increase ozone depleting potential

C

Decrease green house effect

D

Improve water pollution

Question 143 1 Marks

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

A

SO2

B

CO2

C

NH3

D

AIR

Question 144 1 Marks

Which insulating material is poured as liquid?

A

Glass Wool

B

Cork Board

C

Wood Shave

D

Poly Urethane Foam (PUF)

Question 145 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 146 1 Marks

Which refrigerant is inactive to ozone layer?

A

R 12

B

R 13

C

R 22

D

R 134a

Question 147 1 Marks

Which substance absorbs heat and directly changes its state from solid to vapour?

A

Ice

B

Dry ice

C

Primary refrigerants

D

Secondary refrigerants

Question 148 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 149 1 Marks

Which international agency standardises the numbering system for identifying refrigerants?

A

ASHRAE

B

ISHRAE

C

DW142

D

ISO

Question 150 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 151 1 Marks

What does the number 4 of R 134a indicate?

A

Number of hydrogen atoms

B

Number of chlorine atoms

C

Number of carbon atoms

D

Number of fluorine atoms

Question 152 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 153 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 154 1 Marks

What is the category of R 407c refrigerant?

A

Azeotropes

B

Zeotropes

C

Inorganic

D

Organic

Question 155 1 Marks

Why HCFC 22 refrigerant is recycled?

A

Decrease the cost of production

B

Make use of the same lubricant

C

Reduce ODP and GWP of environment

D

Increase the efficiency of RAC systems

Question 156 1 Marks

Which refrigerant is used in domestic refrigerator?

A

R 22

B

R 32

C

R 134 a

D

R 407 c

Question 157 1 Marks

Which refrigerant is highly flammable?

A

HC - Hydro carbon

B

HFC - Hydro fluoro carbon

C

CFC - Chloro fluoro carbon

D

HCFC - Hydro chloro fluoro carbon

Question 158 1 Marks

What is the resistance level of start winding in a refrigerator s compressor motor?

A

Medium resistance

B

High resistance

C

Zero resistance

D

Low resistance

Question 159 1 Marks

How does the evaporator frost affect the sub zero temperature thermally in refrigerator?

A

As conductor

B

As insulator

C

As convector

D

As radiator

Question 160 1 Marks

Which component rejects the maximum heat to ambinet air in refrigerator?

A

Expansion valve

B

Compressor

C

Condenser

D

Evaporator

Question 161 1 Marks

Which terminals are momentarily shorted to start the compressor motor without relay?

A

C and S terminal

B

S and R terminal

C

C and R terminal

D

S and compressor body

Question 162 1 Marks

How the potential relay coil is connected internally to the relay terminals?

A

5 and 1

B

5 and 4

C

5 and 2

D

2 and 4

Question 163 1 Marks

Which refrigerant blend is highly flammable?

A

HCFC

B

HFC

C

CFC

D

HC

Question 164 1 Marks

What is the fault in compressor motor if there is electrical continuity between the dome and motor terminal?

A

Shorted run winding

B

Open common terminal

C

Shorted start winding

D

Grounded compressor motor

Question 165 1 Marks

How the zeotropic refrigerant is taken from the cylinder for charging it into RAC system?

A

Liquid state

B

Vapour state

C

Vapour and liquid

D

Super heated vapour

Question 166 1 Marks

Which component absorbs the maximum heat from the cabinet materials in frost free refrigerator?

A

Condenser

B

Evaporator

C

Compressor

D

Expansion valve

Question 167 1 Marks

Which two tubes act as heat exchanger in a refrigerator?

A

Suction and charging tube

B

Discharge and suction tube

C

Capillary and suction tube

D

Discharge and capillary tube

Question 168 1 Marks

What is the function of refrigerant fluid in a refrigerator?

A

Releases heat inside the cabinet

B

Absorbs heat from inside the cabinet

C

Absorbs heat from outside the cabinet

D

Absorbs heat from bottom side cabinet

Question 169 1 Marks

Which gas is used for pressurising and testing leakage of RAC system?

A

O2

B

N2

C

O3

D

SO2

Question 170 1 Marks

What is the name of heat carrying medium in vapour compression system?

A

Air

B

Water

C

Liquid

D

Refrigerant

Question 171 1 Marks

Which type of motor drive is used in hermetic compressor in refrigerator?

A

Belt drive

B

Gear drive

C

Direct drive

D

Push drive

Question 172 1 Marks

Which method is used to check the leakage of hydro fluoro carbon refrigerants?

A

Electric torch

B

Litmus paper

C

Sulphur candles

D

Electronic leak detector

Question 173 1 Marks

What is ensured before removing a leaky evaporator in a refrigerator?

A

Recharge refrigerant to the system

B

Check the drain tray of evaporator

C

Removal of the thermostat sensor

D

Pressurize the system with refrigerant

Question 174 1 Marks

Which is the hydrocarbon refrigerant?

A

R 12

B

R123

C

R 500

D

R 600a

Question 175 1 Marks

Which part of the refrigerator cools the liquid refrigerant in capillary tube?

A

Discharge line

B

Suction line

C

Condenser

D

Evaporator

Question 176 1 Marks

What is the reason for filter drier sweating in refrigerator?

A

Nitrogen in the system

B

Moisture in the system

C

Oxygen in the system

D

Oil in the system

Question 177 1 Marks

What is the minimum distance to be maintained between the wall and refrigerator condenser?

A

13 cm

B

15 cm

C

18 cm

D

22 cm

Question 178 1 Marks

Which refrigerant property is desirable for V.C system?

A

Low boiling point

B

Corrosive to metals

C

Low latent heat valve

D

Low Dielectric strength

Question 179 1 Marks

Which two terminals read the highest resistance while testing refrigerator compressor motor?

A

Start and run

B

Common and run

C

Start and common

D

Start and compressor body

Question 180 1 Marks

Which process absorbs heat from the cabinet in refrigerator?

A

Expansion

B

Compression

C

Evaporation

D

Condensation

Question 181 1 Marks

Which fan motor speed is used with outdoor unit in split AC?

A

Single speed

B

Double speed

C

Triple speed

D

Five speed

Question 182 1 Marks

What is the cause for noisy fan motor in outdoor unit of split AC?

A

Bearing worn out

B

Motor Burnt

C

Shaft struck

D

Blade bent

Question 183 1 Marks

Which motor is used to drive the blower of indoor unit in ductable split air conditioners?

A

Shaded pole motor

B

Permanent split capacitor motor

C

Three phase induction motor

D

Capacitor start capacitor run motor

Question 184 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 185 1 Marks

How the pressure drop of refrigerant flow is minimised during installation of indoor and outdoor units in ductable split AC?

A

Pipe lines with more joints

B

With more horizontal distance

C

System pipes with minimum bends

D

Install units as far as possible

Question 186 1 Marks

What is the function of starting capacitor in CSIR motor?

A

Gives initial torque

B

Gives running torque

C

Corrects power factor

D

Improves energy efficiency

Question 187 1 Marks

Which component belongs to outdoor unit of split AC?

A

Blower

B

Air filter

C

Compressor

D

Evaporator coil

Question 188 1 Marks

Which horizontal distance is preferred between indoor and outdoor units in ductable split AC installation?

A

15 meters

B

12 meters

C

20 meters

D

25 meters

Question 189 1 Marks

Which material is used to make ducts in split AC?

A

Thermocole

B

GI sheet

C

Wood

D

Fibre

Question 190 1 Marks

Which control opens the compressor motor circuit in the event of continuous overload?

A

Thermostat

B

Fusible plug

C

Bimetal strip

D

Spring loaded relief valve

Question 191 1 Marks

What is the reason for air conditioner running continuously but no cooling effect ?

A

Condensation poor

B

Refrigerant is more

C

Refrigerant leaked

D

Over charged oil

Question 192 1 Marks

What is the advantage of periodical cleaning of air filter?

A

Decrease the volume of air handling

B

Increase the speed of fan motor

C

Decrease the cooling capacity

D

Increase the cooling capacity

Question 193 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 194 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 195 1 Marks

Which type fan blade is used with out door unit of split AC?

A

Vane

B

Guide vane

C

Propeller

D

Centrifugal

Question 196 1 Marks

Which is the mounting location of evaporator in ductable split unit?

A

Floor mounting

B

Wall mounting

C

Ceiling mounting

D

Roof mounting

Question 197 1 Marks

What tonnage capacity of split AC unit uses 150/200 MFD starting capacitor?

A

1 TR

B

1.5 TR

C

2.0 TR

D

2.5 TR

Question 198 1 Marks

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

A

Accumulator

B

Compressor

C

Evaporator

D

Condenser

Question 199 1 Marks

Which type of fan blade is used with indoor unit?

A

Guide vane

B

Blower

C

Axial

D

Vane|

Question 200 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 201 1 Marks

Why the acetylene gas is avoided with copper pipe lines or fittings in oxy-acetylene welding set?

A

Copper is expensive

B

Copper is not flexible hose

C

Copper and acetylene form explosive

D

Copper pipe consumes more acetylene

Question 202 1 Marks

What is the colour of oxygen hose pipe in oxy - acetylene welding set?

A

Maroon

B

Green

C

Black

D

Red

Question 203 1 Marks

What is applied to find the leakage on acetylene gas connection?

A

Soap bubbles

B

Halide torch

C

LPG torch

D

By smell

Question 204 1 Marks

Which flame is used for welding brass?

A

Wide flame

B

Neutral flame

C

Oxidising flame

D

Carburising flame

Question 205 1 Marks

What is the weld test without destroying or breaking the joint?

A

Destructive test

B

Non destructive test

C

Radio graphic test

D

Magnetic test

Question 206 1 Marks

What is done after gas charging and pinching the process tube in refrigerator?

A

Flaring

B

Charging

C

Swaging

D

Brazing

Question 207 1 Marks

What is the precautionary measure taken if flame snaps out and back fires?

A

Shut off both valve quickly and dip in water

B

Shut off oxygen first and acetylene next

C

Shut off acetylene first, oxygen next and dip in water

D

Shut off both valve, oxygen first and dip in water

Question 208 1 Marks

Which gas is produced by the chemical reaction of carbide and water?

A

Oxygen

B

Nitrogen

C

Acetylene

D

Carbon dioxide

Question 209 1 Marks

What is the flame temperature range of oxy acetylene gas flame?

A

1800Degree Centigrade to 2200Degree Centigrade

B

2400Degree Centigrade to 2700Degree Centigrade

C

2700Degree Centigrade to 2800Degree Centigrade

D

3100Degree Centigrade to 3300Degree Centigrade

Question 210 1 Marks

What is the colour of acetylene hose pipe in oxy - acetylene welding set?

A

Maroon

B

Green

C

Black

D

Red

Question 211 1 Marks

Which component secures the hose with regulator union in gas welding set?

A

Steel wire

B

Hose clamp

C

Fibre clip

D

Iron chain

Question 212 1 Marks

What is the fault if excess deposit of tiny metal globules formed on the job surface along weld?

A

Incomplete penetration

B

Slag inclusion

C

Blow hole

D

Spatters

Question 213 1 Marks

Which factor determines the current setting during welding?

A

Types of joint

B

Position of weld

C

Length of electrode

D

Diameter of electrode

Question 214 1 Marks

Which material is used to make electrode holder for welding?

A

Steel

B

Cast iron

C

Cast iron

D

Copper alloy

Question 215 1 Marks

What is the tool used to remove the slag from the welding?

A

Tongs

B

Chipping hammer

C

Cross peen hammer

D

Ball peen hammer

Question 216 1 Marks

What is the purpose of using goggles during chipping the slag from weld bead?

A

To protect eyes

B

To protect hand

C

To protect leg

D

To protect head

Question 217 1 Marks

Why the filler metal does not melt and flow into the joint in bronze welding of copper?

A

Excess use of flux

B

Due to excess of polished surface

C

Surface coated with oxides or oily material

D

Excessive heating of metal s surface

Question 218 1 Marks

Which group the acetylene gas belongs?

A

HC

B

HFC

C

CFC

D

HCFC

Question 219 1 Marks

What is the name of joint between pieces located at right angle to each other?

A

T - Joint

B

Lap joint

C

Butt joint

D

Grooved joint

Question 220 1 Marks

What is the tool used for holding hot metals?

A

Tongs

B

Spanner

C

Pipe vice

D

Bench vice

Question 221 1 Marks

What is the percentage range of silver in copper to copper pipes brazing rod?

A

20 to 35%

B

35 to 45%

C

45 to 60%

D

60 to 100%

Question 222 1 Marks

Which is adjusted to the size of electrode in welding process?

A

Conductor

B

Thickness

C

Length

D

Ampere

Question 223 1 Marks

What is the storage capacity of oxygen cylinder?

A

3 m3

B

5 m3

C

6 m3

D

7 m3

Question 224 1 Marks

What is the safety device used during arc welding?

A

Screw clamp

B

Hand screen

C

Electrode holder

D

Lugs for welding

Question 225 1 Marks

Which valve is closed first while extinguishing flame in gas welding process?

A

Acetylene

B

Hydrogen

C

Oxygen

D

Air

Question 226 1 Marks

Which capacitor is connected in series with starting winding of CSR motor during operation?

A

Fan capacitor|

B

Run capacitor

C

Start capacitor

D

No capacitor is connected

Question 227 1 Marks

What is the value of running capacitor used for 1.5 TR window air conditioner?

A

36 MFD

B

40 MFD

C

80 MFD

D

100 MFD

Question 228 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 229 1 Marks

How to neutralise the concentration of leaked ammonia from air

A

Recover ammonia from air

B

Spraying a lot of water

C

Shut down the plant

D

Spray Hydrochloric acid

Question 230 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 231 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 232 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 233 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

Question 234 1 Marks

Which type of condenser is used in window air conditioner?

A

Fins and tube

B

Plate and tube

C

Plate and coil

D

Bare tube

Question 235 1 Marks

Which type of fan motor is used in window air conditioner?

A

Three phase single shaft motor

B

Single phase single shaft motor

C

Three phase double end shaft motor

D

Single phase double end shaft motor

Question 236 1 Marks

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

A

6000

B

12000

C

18000

D

24000

Question 237 1 Marks

What is the value of starting capacitor used for 1TR window air conditioner?

A

40 MFD

B

60 MFD

C

80 MFD

D

100 MFD

Question 238 1 Marks

Which winding has high inductance value in CSR compressor motor?

A

Common winding

B

Running winding

C

Starting winding

D

Auxiliary winding

Question 239 1 Marks

What is the value of starting capacitor used for 1.5TR capacity window air conditioner?

A

40 to 60 MFD

B

80 to 100 MFD

C

130 to 150 MFD

D

150 to 160 MFD

Question 240 1 Marks

Which device is used to exhaust the room air in window AC?

A

Damper

B

Air filter

C

Filter drier

D

Air washer

Question 241 1 Marks

Where the normally closed contacts are internally connected in voltage relay?

A

Across 1 and 5

B

Across 2 and 5

C

Across 1 and 2

D

Across 2 and 4

Question 242 1 Marks

What is the reason for the compressor does not start but the fan motor works normally in window AC?

A

Defective blower

B

Defective fan motor

C

Defective fan capacitor

D

Defective compressor motor

Question 243 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 244 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 245 1 Marks

Which winding of compressor motor is directly connected across voltage relay coil?

A

Main winding

B

Starting winding

C

Running winding

D

Auxiliary winding

Question 246 1 Marks

Where the relay coil is internally connected in voltage relay?

A

Across 1 and 2

B

Across 5 and 1

C

Across 5 and 2

D

Across 2 and 4

Question 247 1 Marks

Which type of expansion valve is used in window air conditioner?

A

Capillary tube

B

Low side float valve

C

Automatic expansion valve

D

Thermostatic expansion valve

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

A

Relay

B

Starting capacitor

C

Running capacitor

D

Over load protector

Question 250 1 Marks

Which material is used for making fins of condenser in a window air conditioner?

A

Brass

B

Copper

C

Cast iron

D

Aluminium

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

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

What is the atmospheric pressure at sea level?

What is effect of compression process on refrigerant vapour?

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

What is the melting temperature of silver brazing rod?

Which compressor dome handles high pressure and high temperature vapour?

Which instrument is used for measuring heat?

What is the purpose of accumulator in a refrigerator?

Which refrigeration system works on directly by the heat energy?

How the level of heat in a substance is expressed?

Which components maintain the pressure difference in RAC system?

What is the capacity of doing work?

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

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

What is top dead centre in reciprocating compressor cylinder?

Which instrument is used to measure atmospheric pressure?

What is the energy of a body by virtue of its position?

What is the rate of doing work?

What is bottom dead centre in reciprocating compressor cylinder?

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

What is the absolute zero temperature in degree centigrade?

Which thermodynamic process the temperature is kept constant?

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

Which factors produce work?

Which is disconnected by centrifugal switch is RSIR motor?

What is the cause for frequent tripping of circuit breaker while starting a single phase 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?

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

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

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

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

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

Which valve is closed during compression stroke in reciprocating compressor?

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

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

What is the advantage of a hermetically sealed compressor in refrigerator?

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

What is the reason for poor compression?

Which type of rotor is used in 3 Phase induction motor?

Which motor has the least starting torque?

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

Which gas is used for pressure testing the compressor dome?

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

Which winding is made of thick wire in single phase induction motor?

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

Why the top of dome is hot in a scroll compressor?

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

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

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

Which winding has more inductance in refrigerator compressor motor?

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

Which power supply has the fixed polarity?

Which type of conductor is used for bus bars?

What is the unit of electric current?

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

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

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

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

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

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

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

How electrons flow in a battery circuit?

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

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

What is the unit of electrical energy?

What is the unit of capacitance?

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

Which material is used for making disc in energy meter?

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

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?

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

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

How many terminals are there in a Silicon Controlled Rectifier (SCR)?

How the maximum reverse voltage across the diode is termed in reverse biased condition?

How many diodes are required for making a bridge rectifier circuit?

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

What is the atmospheric pressure at sea
level?

What is the melting temperature of silver
brazing rod?

Which instrument is used for measuring
heat?

Which refrigeration system works on
directly by the heat energy?

How the level of heat in a substance is
expressed?

What is the absolute zero temperature in
degree centigrade?

Which is a positive displacement
compressor?

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

Which motor has the least starting
torque?

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

How many diodes are required for making a
bridge rectifier circuit?

What are the passive components used in
electronic circuits?

Which application uses the digital
ICs?

What is the name of electronic
circuit?