Quiz Questions

Question 1 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 2 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 3 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 4 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 5 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 6 1 Marks

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

A

Reciprocating

B

Centrifugal

C

Rotating

D

Orbital

Question 7 1 Marks

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

A

Main

B

Series

C

Starting

D

Running

Question 8 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 9 1 Marks

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

A

Ammeter

B

Voltmeter

C

Ohm meter

D

Anemometer

Question 10 1 Marks

What is the revolving part of induction motor?

A

Stator

B

Rotor

C

Relay

D

Winding

Question 11 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 12 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 13 1 Marks

Which motor has the least starting
torque?

A

CSIR

B

CSR

C

RSIR

D

PSC

Question 14 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 15 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 16 1 Marks

Which gas is used for pressure testing the compressor dome?

A

Air

B

Oxygen

C

Nitrogen

D

Refrigerant

Question 17 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 18 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 19 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 20 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 21 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 22 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 23 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 24 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 25 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 26 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 27 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 28 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 29 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 30 1 Marks

Which refrigerant is inactive to ozone layer?

A

R 12

B

R 13

C

R 22

D

R 134a

Question 31 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 32 1 Marks

Where does the ozone layer exist in atmosphere?

A

Mesosphere

B

Stratosphere

C

Ionosphere

D

Exosphere

Question 33 1 Marks

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

A

SO2

B

CO2

C

NH3

D

AIR

Question 34 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 35 1 Marks

What is the category of R 407c refrigerant?

A

Azeotropes

B

Zeotropes

C

Inorganic

D

Organic

Question 36 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 37 1 Marks

What type of heat is absorbed by primary refrigerant?

A

Total heat

B

Latent heat

C

Specific heat

D

Sensible heat

Question 38 1 Marks

Which international agency standardises the numbering system for identifying refrigerants?

A

ASHRAE

B

ISHRAE

C

DW142

D

ISO

Question 39 1 Marks

Which position is safe for storing refrigerant cylinder?

A

Upside down

B

Horizontal

C

Inclined

D

Upright

Question 40 1 Marks

How many hydrogen atoms are present in R 134a?

A

One

B

Two

C

Four

D

Three

Question 41 1 Marks

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

A

OLP

B

Relay

C

Thermostat

D

Selector switch

Question 42 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 43 1 Marks

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

A

6000

B

12000

C

18000

D

24000

Question 44 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 45 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 46 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 47 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 48 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 49 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 50 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 51 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 52 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 53 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 54 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 55 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 56 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 57 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 58 1 Marks

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

A

3000

B

4000

C

5000

D

6000

Question 59 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 60 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 61 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 62 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 63 1 Marks

Which component is used in frost free refrigerator?

A

Plate coil evaporator

B

Liquid receiver

C

Oil separator

D

Timer switch

Question 64 1 Marks

Which component defrosts in frost free refrigerator?

A

Bulb

B

Heater

C

Thermostat

D

Capillary tube

Question 65 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 66 1 Marks

Which domestic system uses automatic defrost?

A

Frost free refrigerator

B

Conventional refrigerator

C

Split air - conditioner

D

Window air - conditioner

Question 67 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 68 1 Marks

Which component actuates the defrost cycle in frost free refrigerator?

A

Bimetal thermo

B

Defrost heater

C

Timer

D

Relay

Question 69 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 70 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 71 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 72 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 73 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 74 1 Marks

Which device equalizes the system pressure in frost free refrigerator?

A

Capillary tube

B

Compressor

C

Condenser

D

Evaporator

Question 75 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 76 1 Marks

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

A

Thermostat

B

Capacitor

C

Relay

D

OLP

Question 77 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 78 1 Marks

Which device protects the compressor motor from drawing more current?

A

OLP

B

Relay

C

Thermostat

D

Door switch

Question 79 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 80 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 81 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 82 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 83 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 84 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 85 1 Marks

What is the equivalent absolute scale for centigrade?

A

Kelvin

B

Celsius

C

Rankine

D

Fahrenheit

Question 86 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 87 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 88 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 89 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 90 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 91 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 92 1 Marks

Which factors produce work?

A

Force and distance

B

Time and distance

C

Force and power

D

Force and time

Question 93 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 94 1 Marks

Which instrument is used to measure atmospheric pressure?

A

Hygrometer

B

Hydrometer

C

Manometer

D

Barometer

Question 95 1 Marks

What is the advantage of using flux in brazing?

A

Over heating

B

Melting tubes

C

Prevent Oxidation

D

Chemical reaction

Question 96 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 97 1 Marks

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

A

Thermoheater

B

Defrost timer

C

Relay

D

OLP

Question 98 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 99 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 100 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

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

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

What is the reason for poor compression?

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

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

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

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

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

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

What is the revolving part of induction motor?

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

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

Which motor has the least starting torque?

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

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

Which gas is used for pressure testing the compressor dome?

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

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

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

Which valve is closed during compression stroke in reciprocating compressor?

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

Why universal numbering system is adopted for different refrigerants?

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

What does the number 4 of R 134a indicate?

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

What is the effect of releasing HCFC refrigerants to atmosphere?

Which property is desirable for an ideal refrigerant?

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

What is the desirable property of POE lubricant?

Which refrigerant is inactive to ozone layer?

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

Where does the ozone layer exist in atmosphere?

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

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

What is the category of R 407c refrigerant?

Which is the green house gas?

What type of heat is absorbed by primary refrigerant?

Which international agency standardises the numbering system for identifying refrigerants?

Which position is safe for storing refrigerant cylinder?

How many hydrogen atoms are present in R 134a?

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

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

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

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

Which winding has high inductance value in CSR compressor motor?

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

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

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

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

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

What is the reason for Compressor does not start ?

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

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

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

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

Which type of compressor is used in window air conditioner?

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

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

Which type of condenser is used in window air conditioner?

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

Which type of evaporator is used in frost free refrigerator?

Where the thermal bulb is fixed in frost free refrigerator?

Which component is used in frost free refrigerator?

Which component defrosts in frost free refrigerator?

Where the manually defrosted water is stored in refrigerator?

Which domestic system uses automatic defrost?

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

Which component actuates the defrost cycle in frost free refrigerator?

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

Which component is turned off while defrost heater is energised?

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

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

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

Which device equalizes the system pressure in frost free refrigerator?

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

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

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

Which device protects the compressor motor from drawing more current?

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

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

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

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

Which motor has the least starting
torque?

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

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

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

Which refrigeration system works on
directly by the heat energy?

What is the melting temperature of silver
brazing rod?

What is the absolute zero temperature in
degree centigrade?