Quiz Questions

Question 1 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 2 1 Marks

How the level of heat in a substance is
expressed?

A

Micron

B

Pressure

C

Humidity

D

Temperature

Question 3 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 4 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 5 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 6 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 7 1 Marks

What is the capacity of doing work?

A

Work

B

Power

C

Force

D

Energy

Question 8 1 Marks

What is the advantage of using flux in brazing?

A

Over heating

B

Melting tubes

C

Prevent Oxidation

D

Chemical reaction

Question 9 1 Marks

Which instrument is used to measure atmospheric pressure?

A

Hygrometer

B

Hydrometer

C

Manometer

D

Barometer

Question 10 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 11 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 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

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

A

Thermoheater

B

Defrost timer

C

Relay

D

OLP

Question 14 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 15 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 16 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 17 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 18 1 Marks

What is the equivalent absolute scale for centigrade?

A

Kelvin

B

Celsius

C

Rankine

D

Fahrenheit

Question 19 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 20 1 Marks

Which instrument is used for measuring
heat?

A

Thermometer

B

Anemometer

C

Calorimeter

D

Ammeter

Question 21 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 22 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 23 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 24 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 25 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 26 1 Marks

How to change the direction of rotation in
3 Phase induction motor?

A

Change neutral

B

Change all phase

C

Change any two phase

D

Change the winding only

Question 27 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 28 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 29 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 30 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 31 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 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 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 34 1 Marks

Which motor has the least starting
torque?

A

CSIR

B

CSR

C

RSIR

D

PSC

Question 35 1 Marks

Which winding is made of thin wire in single phase motor?

A

Main

B

Series

C

Starting

D

Running

Question 36 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 37 1 Marks

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

A

Ammeter

B

Voltmeter

C

Ohm meter

D

Anemometer

Question 38 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 39 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 40 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 41 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 42 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 43 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 44 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 45 1 Marks

Which is a positive displacement
compressor?

A

Centrifugal compressor

B

Scroll compressor

C

Water pump

D

Oil pump

Question 46 1 Marks

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

A

Starting

B

Running

C

Auxiliary

D

Additional

Question 47 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 48 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 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 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 51 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 52 1 Marks

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

A

Petrol

B

Grease

C

Shellac

D

Kerosene

Question 53 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 54 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 55 1 Marks

Which material is used for making disc in energy meter?

A

Aluminium

B

Copper

C

Brass

D

Zinc

Question 56 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 57 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 58 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 59 1 Marks

What is the unit of capacitance?

A

Volt

B

Ampere

C

Farad

D

Coulomb

Question 60 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 61 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 62 1 Marks

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

A

Voltage

B

Current

C

Resistance

D

Conductance

Question 63 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 64 1 Marks

Which winding has more inductance in refrigerator compressor motor?

A

Run

B

Start

C

Common

D

Start and common

Question 65 1 Marks

What is the unit of electrical energy?

A

Volt

B

Watt

C

Ampere

D

Kilo watt hour

Question 66 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 67 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 68 1 Marks

Which type of conductor is used for bus bars?

A

Solid conductor

B

Thermal conductor

C

Stranded conductor

D

Standard conductor

Question 69 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 70 1 Marks

What is the unit of electric current?

A

Ampere

B

Farad

C

Ohm

D

Volt

Question 71 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 72 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 73 1 Marks

Which power supply has the fixed polarity?

A

Direct current

B

Signal voltage

C

Signal ripples

D

Alternating current

Question 74 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 75 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 76 1 Marks

Which semiconductor material is used to make diodes?

A

Steel

B

Silicon

C

Copper

D

Aluminium

Question 77 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 78 1 Marks

What is the method of converting AC to DC
power supply with two diodes and a step down
transformer?

A

Bridge rectifier

B

Full wave rectifier

C

Half wave rectifier

D

Medium wave rectifier

Question 79 1 Marks

What is the unit of capacitance used with single phase induction motors in domestic RAC system?

A

Kilo ohm

B

Microfarad

C

Milli henry

D

Milli ampere

Question 80 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 81 1 Marks

Which device maintains a constant DC output?

A

Load regulators

B

Rectifier circuits

C

Current limiters

D

Voltage regulators

Question 82 1 Marks

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

A

Transistor

B

TRIAC

C

DIAC

D

SCR

Question 83 1 Marks

Which electronic component is the voltage regulator?

A

Zener diode

B

Transistor

C

Triac

D

Diac

Question 84 1 Marks

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

A

One

B

Two

C

Four

D

Three

Question 85 1 Marks

Which material is used for making ICs?

A

Silicon

B

Carbon

C

Platinum

D

Mild steel

Question 86 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 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

What is the unit of inductance?

A

Ohm

B

Henry

C

Farad

D

Ampere

Question 89 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 90 1 Marks

Which material is used for making zener diode?

A

Lead

B

Silicon

C

Titanium

D

Platinum

Question 91 1 Marks

Which type of diode is used for communication circuits?

A

Signal diode

B

Zener diode

C

Rectifier diode

D

Switching diode

Question 92 1 Marks

Which application uses the digital
ICs?

A

Amplifier

B

Logic gates

C

Tuned circuits

D

Voltage regulator

Question 93 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 94 1 Marks

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

A

Inversion

B

Regulation

C

Convection

D

Rectification

Question 95 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 96 1 Marks

Which medium is used to extinguish Class - A fire?

A

CO2

B

Foam

C

Water

D

Dry powder

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

Which materials are used to make mallets?

A

Wood, cast iron

B

Wood, rubber

C

Rubber, brass

D

Wood, brass

Question 99 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 100 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 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 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 103 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 104 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 105 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 106 1 Marks

Which tool is used for bending long sheet metal?

A

Folding bar

B

Bench vice

C

Hand vice

D

Shear

Question 107 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 108 1 Marks

Which extinguishes the fire on electrical equipment?

A

Oil

B

Foam

C

Water

D

Halon

Question 109 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 110 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 111 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 112 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 113 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 114 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 115 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 116 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 117 1 Marks

How the capacity of refrigerator is expressed?

A

Weightage

B

Tonnage

C

Wattage

D

Litres

Question 118 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 119 1 Marks

Which device protects the compressor motor from drawing more current?

A

OLP

B

Relay

C

Thermostat

D

Door switch

Question 120 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 121 1 Marks

Which device equalizes the system pressure in frost free refrigerator?

A

Capillary tube

B

Compressor

C

Condenser

D

Evaporator

Question 122 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 123 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 124 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 125 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 126 1 Marks

Which component is used in frost free refrigerator?

A

Plate coil evaporator

B

Liquid receiver

C

Oil separator

D

Timer switch

Question 127 1 Marks

Which component defrosts in frost free refrigerator?

A

Bulb

B

Heater

C

Thermostat

D

Capillary tube

Question 128 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 129 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 130 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 131 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 132 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 133 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 134 1 Marks

What is the effect of contamination in refrigeration system?

A

High heating

B

Poor cooling

C

Low pressure

D

Low humidity

Question 135 1 Marks

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

A

Thermostat

B

Capacitor

C

Relay

D

OLP

Question 136 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 137 1 Marks

Which component actuates the defrost cycle in frost free refrigerator?

A

Bimetal thermo

B

Defrost heater

C

Timer

D

Relay

Question 138 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 139 1 Marks

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

A

Bimetal thermo

B

Thermostat

C

Relay

D

Timer

Question 140 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 141 1 Marks

Which is the hydrocarbon refrigerant?

A

R 12

B

R123

C

R 500

D

R 600a

Question 142 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 143 1 Marks

Which refrigerant is used in domestic refrigerator?

A

R 22

B

R 32

C

R 134 a

D

R 407 c

Question 144 1 Marks

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

A

Expansion valve

B

Compressor

C

Condenser

D

Evaporator

Question 145 1 Marks

What is the full form of the relay - PTC?

A

Positive temperature coefficient

B

Permanent temperature control

C

Polar terminal checking

D

Positive terminal circuit

Question 146 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 147 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 148 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 149 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 150 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 151 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 152 1 Marks

Which type of compressor is used as a vacuum pump?

A

Reciprocating

B

Centrifugal

C

Rotary

D

Scroll

Question 153 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 154 1 Marks

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

A

O2

B

N2

C

O3

D

SO2

Question 155 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 156 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 157 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 158 1 Marks

Which refrigerant blend is highly flammable?

A

HCFC

B

HFC

C

CFC

D

HC

Question 159 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 160 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 161 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 162 1 Marks

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

A

Air

B

Water

C

Liquid

D

Refrigerant

Question 163 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 164 1 Marks

Which process absorbs heat from the cabinet in refrigerator?

A

Expansion

B

Compression

C

Evaporation

D

Condensation

Question 165 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 166 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 167 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 168 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 169 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 170 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 171 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 172 1 Marks

Which component belongs to indoor unit of split AC?

A

Compressor

B

Condenser

C

Evaporator

D

Drier

Question 173 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 174 1 Marks

How many fan motors are used in split AC?

A

Two

B

Five

C

Four

D

Three

Question 175 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 176 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 177 1 Marks

Which component belongs to outdoor unit of split AC?

A

Blower

B

Air filter

C

Compressor

D

Evaporator coil

Question 178 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 179 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 180 1 Marks

What is the function of remote control in split AC?

A

Humidity setting

B

Pressure setting

C

Drain water control

D

Transmits signal to operate AC

Question 181 1 Marks

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

A

Accumulator

B

Compressor

C

Evaporator

D

Condenser

Question 182 1 Marks

Which type of fan blade is used with indoor unit?

A

Guide vane

B

Blower

C

Axial

D

Vane|

Question 183 1 Marks

Which material is used to make ducts in split AC?

A

Thermocole

B

GI sheet

C

Wood

D

Fibre

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 function of starting capacitor in CSIR motor?

A

Gives initial torque

B

Gives running torque

C

Corrects power factor

D

Improves energy efficiency

Question 186 1 Marks

Which type of switch is used to control the room air temperature in split AC?

A

Over load protector

B

Thermostat switch

C

Manual switch

D

Thermal relay

Question 187 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 188 1 Marks

What is the reason for poor condensation in split AC?

A

High ambient temperature

B

Low ambient temperature

C

Condenser tube leaky

D

Blower motor failure

Question 189 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 190 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 191 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 192 1 Marks

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

A

3000

B

4000

C

5000

D

6000

Question 193 1 Marks

Which capacity of fan motor is used in 1Ton window air conditioner?

A

1/5 HP

B

1/10 HP

C

1/16 HP

D

1/20 HP

Question 194 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 195 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 196 1 Marks

Where the filter drier is installed in window AC refrigerant circuit?

A

Discharge line

B

Suction line

C

Service line

D

Liquid line

Question 197 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 198 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

Question 199 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 200 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 201 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 202 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 203 1 Marks

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

A

6000

B

12000

C

18000

D

24000

Question 204 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 205 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 206 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 207 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 208 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 209 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 210 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 211 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 212 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 213 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 214 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 215 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 216 1 Marks

Which refrigerant is inactive to ozone layer?

A

R 12

B

R 13

C

R 22

D

R 134a

Question 217 1 Marks

How many hydrogen atoms are present in R 134a?

A

One

B

Two

C

Four

D

Three

Question 218 1 Marks

How to prevent the small pieces of glass wool affecting the eyes?

A

Wearing goggles

B

Wearing gloves

C

Using mask

D

Using shoes

Question 219 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 220 1 Marks

Which international agency standardises the numbering system for identifying refrigerants?

A

ASHRAE

B

ISHRAE

C

DW142

D

ISO

Question 221 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 222 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 223 1 Marks

What is the category of R 290 refrigerant?

A

Halocarbons

B

Azeotropes

C

Hydrocarbons

D

Organic compounds

Question 224 1 Marks

What is the category of R 502 refrigerant?

A

Azeotropes

B

Halocarbon

C

Hydrocarbon

D

Organic compounds

Question 225 1 Marks

Where does the ozone layer exist in atmosphere?

A

Mesosphere

B

Stratosphere

C

Ionosphere

D

Exosphere

Question 226 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 227 1 Marks

What is the cylinder colour code of R 22 refrigerant?

A

White

B

Green

C

Orchid

D

Orange

Question 228 1 Marks

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

A

0

B

1

C

2

D

3

Question 229 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 230 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 231 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 232 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 233 1 Marks

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

A

SO2

B

CO2

C

NH3

D

AIR

Question 234 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 235 1 Marks

Which is the inorganic refrigerant?

A

R 170

B

R 500

C

R 630

D

R 717

Question 236 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 237 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 238 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 239 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 240 1 Marks

What type of heat is absorbed by primary refrigerant?

A

Total heat

B

Latent heat

C

Specific heat

D

Sensible heat

Question 241 1 Marks

Which flame is used for welding brass?

A

Wide flame

B

Neutral flame

C

Oxidising flame

D

Carburising flame

Question 242 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 243 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 244 1 Marks

How the cylinders of gas welding set are secured in trolley?

A

By cable

B

Using chain

C

Tightened with rope

D

Tied up with belt

Question 245 1 Marks

What is the storage capacity of oxygen cylinder?

A

3 m3

B

5 m3

C

6 m3

D

7 m3

Question 246 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 247 1 Marks

Which material is used to make electrode holder for welding?

A

Steel

B

Cast iron

C

Cast iron

D

Copper alloy

Question 248 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 249 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 250 1 Marks

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

A

Flaring

B

Charging

C

Swaging

D

Brazing

Question 251 1 Marks

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

A

Maroon

B

Green

C

Black

D

Red

Question 252 1 Marks

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

A

Oxygen

B

Nitrogen

C

Acetylene

D

Carbon dioxide

Question 253 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 254 1 Marks

How much volume of oxygen is needed for complete combustion of one unit volume of acetylene?

A

1.5 times

B

2.5 times

C

3.5 times

D

4.5 times

Question 255 1 Marks

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

A

Conductor

B

Thickness

C

Length

D

Ampere

Question 256 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 257 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 258 1 Marks

Which group the acetylene gas belongs?

A

HC

B

HFC

C

CFC

D

HCFC

Question 259 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 260 1 Marks

What is the ratio of oxygen to acetylene in neutral flame for brazing?

A

01:03

B

02:01

C

01:01

D

01:02

Question 261 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 262 1 Marks

What is the tool used for holding hot metals?

A

Tongs

B

Spanner

C

Pipe vice

D

Bench vice

Question 263 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 264 1 Marks

Which is the welding method if the filler rod only is fused?

A

Non fusion

B

Pressure

C

Fusion

D

Forge

Question 265 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 266 1 Marks

What is the purpose of chemical spraying on finned condenser?

A

Flush out the condenser tubes

B

Remove the rust on the fins

C

Blow the dust from the fins

D

Correct the bends in fins

Question 267 1 Marks

What is the physical change of refrigerant in evaporator?

A

Solid to liquid

B

Vapour to solid

C

Liquid to vapour

D

Vapour to liquid

Question 268 1 Marks

Which is the constant reference for the working of AEV?

A

Oil temperature

B

Suction pressure

C

Volume expansion

D

Discharge pressure

Question 269 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 270 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 271 1 Marks

Which type of condenser is used in window Air conditioner?

A

Natural convection

B

Forced convection

C

Water cooled

D

Evaporative

Question 272 1 Marks

Which cooling medium is used to condense the refrigerant vapour in plate and tube condenser?

A

Natural Air

B

Forced Air

C

Water

D

Brine solution

Question 273 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 274 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 275 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 276 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 277 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 278 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 279 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 280 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 281 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 282 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 283 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 284 1 Marks

Which component is connected in series with defrost heater in a frost free refrigerator?

A

Door switch

B

Cabinet bulb

C

Bimetal thermo

D

Heating element

Question 285 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 286 1 Marks

Which colour is used for painting condenser coil?

A

Green

B

Black

C

Blue

D

Red

Question 287 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 288 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 289 1 Marks

Which device meters the amount of refrigerant entering the evaporator in window AC?

A

Accumulator

B

Capillary tube

C

Heat exchanger

D

Finned tube condenser

Question 290 1 Marks

Which type of evaporator is used in house hold refrigerator?

A

Plate evaporator

B

Tube in tube evaporator

C

Shell and coil evaporator

D

Shell and tube evaporator

Question 291 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 292 1 Marks

Which factors produce work?

A

Force and distance

B

Time and distance

C

Force and power

D

Force and time

Question 293 1 Marks

What is the rate of doing work?

A

Duty

B

Force

C

Power

D

Velocity

Question 294 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 295 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 296 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 297 1 Marks

What is the advantage of inverter split AC?

A

Eliminates compressor

B

High energy efficiency

C

Low energy efficiency

D

Current drawn is high

Question 298 1 Marks

Which device switches ON/OFF the car AC compressor?

A

Crank shaft

B

Blower unit

C

Rotor winding

D

Magnetic clutch

Question 299 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 300 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 301 1 Marks

Which insulating material is used in duct work?

A

Wood

B

Plastic

C

Rubber

D

Glass wool

Question 302 1 Marks

Which type of fan blade is used with indoor unit?

A

Guide vane

B

Blower

C

Axial

D

Vane|

Question 303 1 Marks

What is the use of anemometer?

A

Check water flow

B

Measure air flow

C

Produce current

D

Measure voltage

Question 304 1 Marks

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

A

Nitrogen

B

Oxygen

C

Moisture

D

Non condensable gases

Question 305 1 Marks

What is the purpose of providing gas ballast in two stage rotary vacuum pump?

A

Avoid condensation of water vapour

B

Prevent condensation of nitrogen

C

Prevent condensation of dry air

D

Avoid condensation of refrigerant

Question 306 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 307 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 308 1 Marks

What is the cause for noise in indoor unit of a multi split air conditioner?

A

Refrigerant leak

B

Blower is loosened

C

Running current is high

D

Compressor not working

Question 309 1 Marks

What is the reason for poor condensation in split AC?

A

High ambient temperature

B

Low ambient temperature

C

Condenser tube leaky

D

Blower motor failure

Question 310 1 Marks

What type of compressor motor is used in inverter split AC?

A

Constant speed compressor motor

B

Centrifugal compressor motor

C

Open type compressor motor

D

Variable speed motor

Question 311 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 312 1 Marks

Which component belongs to indoor unit of split AC?

A

Compressor

B

Condenser

C

Evaporator

D

Drier

Question 313 1 Marks

What is the test pressure of cooling coils during manufacture?

A

150 psig

B

250 psig

C

350 psig

D

450 psig

Question 314 1 Marks

Which material is used to make ducts in split AC?

A

Thermocole

B

GI sheet

C

Wood

D

Fibre

Question 315 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 316 1 Marks

What is ensured before starting a vacuum pump?

A

Correct oil level

B

Capacity of the pump

C

Weight of vacuum pump

D

Available ac power supply

Question 317 1 Marks

Which is the accurate method of refrigerant charging in car AC?

A

Weighing method

B

Dial a charge method

C

Suction pressure method

D

Sight glass bubbles method

Question 318 1 Marks

What is the function of remote control in split AC?

A

Humidity setting

B

Pressure setting

C

Drain water control

D

Transmits signal to operate AC

Question 319 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 320 1 Marks

How many fan motors are used in split AC?

A

Two

B

Five

C

Four

D

Three

Question 321 1 Marks

What is the effect of increased out door temperature in car AC?

A

Compressor runs more time

B

Compressor runs less time

C

Performance remains the same

D

Performance increases

Question 322 1 Marks

What are the multi speed of blower motor used in indoor unit of ductable split air conditioner?

A

ow - 500 rpm, medium - 550rpm, high - 720 rpm

B

Low - 800 rpm, medium - 850rpm, high - 920 rpm

C

Low - 900 rpm, medium - 950rpm, high - 1100 rpm

D

Low -1000 rpm, medium -1200rpm, high -1350 rpm

Question 323 1 Marks

What is the cause of water leakage in indoor unit of multi split AC?

A

Efficient water pump

B

Drain line not properly installed

C

Condenser water pump defective

D

Over flow of water from cooling tower sump

Question 324 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 325 1 Marks

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

A

Accumulator

B

Compressor

C

Evaporator

D

Condenser

Question 326 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 327 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 328 1 Marks

Which refrigerant control is used in car AC?

A

Hand shut off valve

B

Automatic expansion valve

C

Thermostatic expansion valve

D

Thermal electric expansion valve

Question 329 1 Marks

What is the maximum TR capacity operated with Single phase AC supply?

A

1.00 TR

B

1.5 TR

C

2.0 TR

D

5 TR

Question 330 1 Marks

What is the effect of operating the compressor under 5 of Hg vacuum during pump down process?

A

Pumps oil to condenser

B

Prevent motor damage in dome

C

Prevent leakage in service valve

D

Prevent piston damage

Question 331 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 332 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 333 1 Marks

What is the cooling capacity for 1.5 Ton of ductable split air conditioner?

A

3500 Kcal/hr

B

4000 Kcal/hr

C

4500 Kcal/hr

D

5000 Kcal/hr

Question 334 1 Marks

What is the differential of control switch if it cuts in at 29 kg/cm2 and cuts out at 34 kg/cm2?

A

5 kg / cm2

B

10 kg / cm2

C

15 kg / cm2

D

20 kg / cm2

Question 335 1 Marks

What is the effect of longer suction and liquid piping in AC?

A

No pressure rise

B

More pressure drop

C

Less pressure drop

D

Medium pressure rise

Question 336 1 Marks

Which is sensed by TEV in response to heat load variation?

A

Sub cool in liquid line

B

Discharge temperature

C

Super heat in suction line

D

Evaporating temperature

Question 337 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 338 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 339 1 Marks

Where the liquid refrigerant is stored in multi split Air-conditioner during pump down operation?

A

Evaporator

B

Condenser

C

Accumulator

D

Liquid receiver

Question 340 1 Marks

Which bearing is used in blower motor of indoor unit in ductable split air conditioner?

A

Ball bearing

B

Thrust bearing

C

Sleeve bearing

D

Open ball bearing

Question 341 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 342 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 343 1 Marks

What is the advantage of ductable air conditioner over window air conditioner?

A

Higher cost

B

Noisy operation

C

Silent operation

D

Needs more space

Question 344 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 345 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 346 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 347 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 348 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 349 1 Marks

What is the advantage of multi split air conditioners?

A

One outdoor unit for one indoor unit

B

two outdoor units for one indoor unit

C

Several outdoor units for one indoor unit

D

One outdoor unit for several indoor units

Question 350 1 Marks

Which device engages the compressor shaft in car AC?

A

Thermo switch

B

Car engine pulley

C

Over load protector

D

Electro magnetic clutch

Question 351 1 Marks

What is the test pressure of condenser coils during manufacture?

A

450 psig

B

350 psig

C

250 psig

D

150 psig

Question 352 1 Marks

Which type of switch is used to control the room air temperature in split AC?

A

Over load protector

B

Thermostat switch

C

Manual switch

D

Thermal relay

Question 353 1 Marks

Which level of vacuum is required before charging HFC 134a in car AC?

A

500 micron

B

400 micron

C

300 micron

D

200 micron

Question 354 1 Marks

Which component belongs to outdoor unit of split AC?

A

Blower

B

Air filter

C

Compressor

D

Evaporator coil

Question 355 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 356 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 357 1 Marks

Which material is used for making service valve?

A

Brass

B

Cast iron

C

Aluminium

D

Stainless steel

Question 358 1 Marks

What is ensured before mounting condenser in car AC?

A

Accessibility for future service

B

Condenser top line to TEV inlet

C

Condenser in line with car radiator

D

Condenser bottom line to discharge line

Question 359 1 Marks

Which part of car AC compressor actuates the piston directly?

A

Crank shaft and connecting rod

B

Rotor and stator

C

Swash plate

D

Blower unit

Question 360 1 Marks

Which safety control is electrically connected in series with magnetic clutch of compressor in car AC?

A

TEV

B

AEV

C

HPC

D

EEV

Question 361 1 Marks

Which is the source of drive for compressor shaft in car AC?

A

Magnetic clutch

B

Condenser fan

C

Engine shaft

D

Blower fan

Question 362 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 363 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 364 1 Marks

Which part of the compressor converts rotary into reciprocating motion of piston in car AC?

A

Connecting rod

B

Magnetic clutch

C

Swash plate

D

Crank shaft

Question 365 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 366 1 Marks

How many speed selection is used with indoor air blower in ductable multi split AC?

A

One - speed

B

Two - speed

C

Three - speed

D

Four - speed

Question 367 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 368 1 Marks

What is the cause of reduction in fan's air flow?

A

Leak in the system

B

Fan capacitor is weak

C

Refrigerant under charge

D

Supply voltage is normal

Question 369 1 Marks

What is indicated by the bubbles in car AC's sight glass?

A

Pressure of air

B

Poor compression

C

Excess of refrigerant

D

Shortage of refrigerant

Question 370 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 371 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 372 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 373 1 Marks

Which part of window AC removes dust particles from the room air?

A

Strainer

B

Air filter

C

Filter drier

D

Dehydrator

Question 374 1 Marks

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

A

OLP

B

Relay

C

Thermostat

D

Selector switch

Question 375 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 376 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 377 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 378 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 379 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 380 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 381 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 382 1 Marks

What is the remedy for the defective OLP in a window air conditioner?

A

Repair the OLP

B

Replace the OLP

C

Remove the parts

D

Repair the heater element

Question 383 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 384 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 385 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 386 1 Marks

What is the capacity of compressor motor used in 1Ton window air conditioner?

A

0.50 HP

B

0.75 HP

C

0.95 HP

D

1.00 HP

Question 387 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 388 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 389 1 Marks

Which gas is used for pressure testing the compressor dome?

A

Air

B

Oxygen

C

Nitrogen

D

Refrigerant

Question 390 1 Marks

What is the revolving part of induction motor?

A

Stator

B

Rotor

C

Relay

D

Winding

Question 391 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 392 1 Marks

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

A

One

B

Two

C

Four

D

Three

Question 393 1 Marks

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

A

SCR

B

Diode

C

Capacitor

D

Zener diode

Question 394 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 395 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 396 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 397 1 Marks

Which domestic system uses automatic defrost?

A

Frost free refrigerator

B

Conventional refrigerator

C

Split air - conditioner

D

Window air - conditioner

Question 398 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 399 1 Marks

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

A

Maroon

B

Green

C

Black

D

Red

Question 400 1 Marks

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

A

Acetylene

B

Hydrogen

C

Oxygen

D

Air

Question 401 1 Marks

Which method of welding process is suitable to nonferrous dissimilar metals?

A

Cold welding

B

Explosion welding

C

Brazing and bronze welding

D

Ultrasonic method of welding

Question 402 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

What is the melting temperature of silver brazing rod?

How the level of heat in a substance is expressed?

What is the absolute zero temperature in degree centigrade?

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

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

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

What is the capacity of doing work?

What is the advantage of using flux in brazing?

Which instrument is used to measure atmospheric pressure?

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

What is top dead centre in reciprocating compressor cylinder?

Which components maintain the pressure difference in RAC system?

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

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

What is bottom dead centre in reciprocating compressor cylinder?

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

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

What is the equivalent absolute scale for centigrade?

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

Which instrument is used for measuring heat?

What is the purpose of accumulator in a refrigerator?

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?

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

How to change the direction of rotation in 3 Phase induction motor?

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

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

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

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

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

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

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

Which motor has the least starting torque?

Which winding is made of thin wire in single phase motor?

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

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

Which type of compressor is used for domestic refrigerator?

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

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

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

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

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

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

Which is a positive displacement compressor?

Which winding is made of thick wire in single phase 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?

Which is disconnected by centrifugal switch is RSIR motor?

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

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

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

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

How electrons flow in a battery circuit?

Which material is used for making disc in energy meter?

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

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

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

What is the unit of capacitance?

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

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

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

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

Which winding has more inductance in refrigerator compressor motor?

What is the unit of electrical energy?

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

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

Which type of conductor is used for bus bars?

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

What is the unit of electric current?

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

Which power supply has the fixed polarity?

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

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

Which semiconductor material is used to make diodes?

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

What is the method of converting AC to DC power supply with two diodes and a step down transformer?

What is the unit of capacitance used with single phase induction motors in domestic RAC system?

What is the melting temperature of silver
brazing rod?

How the level of heat in a substance is
expressed?

What is the absolute zero temperature in
degree centigrade?

Which instrument is used for measuring
heat?

What is the atmospheric pressure at sea
level?

How to change the direction of rotation in
3 Phase induction motor?

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

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

Which motor has the least starting
torque?

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

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

Which is a positive displacement
compressor?

What is the method of converting AC to DC
power supply with two diodes and a step down
transformer?

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?