Quiz Questions

Question 1 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 2 1 Marks

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

A

Blower

B

Door switch

C

Cabinet bulb

D

Defrost heater

Question 3 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 4 1 Marks

Which instrument is used to measure atmospheric pressure?

A

Hygrometer

B

Hydrometer

C

Manometer

D

Barometer

Question 5 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 6 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 7 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 8 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 9 1 Marks

What is the storage capacity of oxygen cylinder?

A

3 m3

B

5 m3

C

6 m3

D

7 m3

Question 10 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 11 1 Marks

Which refrigerant blend is highly flammable?

A

HCFC

B

HFC

C

CFC

D

HC

Question 12 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 13 1 Marks

Why the water flow switch is bypassed to test the HP control switch in package AC?

A

Make the unit not to trip

B

Raise the oil pressure more

C

Stopping the unit immediately

D

Lower the head pressure in compressor

Question 14 1 Marks

Which winding has more inductance in refrigerator compressor motor?

A

Run

B

Start

C

Common

D

Start and common

Question 15 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 16 1 Marks

What parameters are checked if the uneven cooling prevails at different rooms in a chiller plant?

A

Compressor current drawn

B

Condenser water pump ampere

C

Cooling tower fan motor ampere

D

Chilled water pump current drawn

Question 17 1 Marks

What is meant by total pressure in a duct?

A

Velocity pressure - static pressure

B

Static pressure + velocity pressure

C

Velocity pressure + suction pressure

D

Suction pressure + discharge pressure

Question 18 1 Marks

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

A

All grille temperatures

B

Liquid line temperature

C

Inlet and outlet temperature of chillier

D

Temperatures in chilled water system

Question 19 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 20 1 Marks

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

A

Study about the plant

B

Judge quality of water

C

Checking the hardness of water

D

Fix descaling time for condenser

Question 21 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 22 1 Marks

What is the minimum cross sectional area of the ducts used with bus AC?

A

400 cm2

B

500 cm2

C

600 cm2

D

700 cm2

Question 23 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 24 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 25 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 26 1 Marks

What is the purpose of gland packing in water line valves of chiller AC plant?

A

Prevent leakage

B

Control water flow

C

Reduce valve noise

D

Smooth handling of valve

Question 27 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 28 1 Marks

Which material is used for making ICs?

A

Silicon

B

Carbon

C

Platinum

D

Mild steel

Question 29 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 30 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 31 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 32 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 33 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 34 1 Marks

What is the absolute pressure of gas cylinder if the gauge reads 15.3 p.s.i.g?

A

10 p.s.i.a

B

20 p.s.i.a

C

30 p.s.i.a

D

40 p.s.i.a

Question 35 1 Marks

Which gas is used for flushing blocked capillary tube?

A

Moist air

B

Hydrogen

C

Dry nitrogen

D

Aqua ammonia

Question 36 1 Marks

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

A

Voltage

B

Current

C

Resistance

D

Conductance

Question 37 1 Marks

Which tool is used to straighten the deformed fins of air cooled condenser?

A

Blower

B

Fin comb

C

Wire brush

D

Brass brush

Question 38 1 Marks

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

A

Avoid oil foaming

B

Prevent liquid entry to compressor

C

Increase current of the compressor motor

D

To lower the suction pressure close to 0.5 kg/cm2

Question 39 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 40 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 41 1 Marks

Which parameter of heater element is increased in OLP due to hot compressor dome?

A

Voltage

B

Resistance

C

Capacitance

D

Magnetic field

Question 42 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 43 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 44 1 Marks

What is the purpose of using the water cooled condenser in industrial AC plant?

A

Reduce the pressure

B

Increase the temperature

C

Reject more heat to water

D

Absorb less heat from system

Question 45 1 Marks

Which switch is interlocked to become on if the power isolator is off in package AC?

A

Thermostat

B

Blower motor

C

Crankcase heater

D

Compressor starting

Question 46 1 Marks

Which thermistor s resistance increases if the temperature is decreased?

A

PTC

B

NTC

C

VDR

D

LDR

Question 47 1 Marks

How to safe guard the hands while handling glass wool?

A

Wearing goggles

B

Wearing gloves

C

Using mask

D

Using shoes

Question 48 1 Marks

What is the effect of partially choked thermostatic expansion valve in central AC plant?

A

Iced condenser

B

Frosted evaporator

C

Hot expansion valve

D

Frosted expansion valve

Question 49 1 Marks

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

A

OLP

B

Relay

C

Thermostat

D

Selector switch

Question 50 1 Marks

Why the stainless-steel metal is used to make evaporator in ice plant?

A

Erosive

B

Galvanic

C

Reactive

D

Non corrosive

Question 51 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 52 1 Marks

What are the causes for blockage in
capillary tube?

A

Non condensable gases

B

Moisture and wax from oil

C

Solid particles

D

Over charging of refrigerant

Question 53 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 54 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 55 1 Marks

Which component is used in frost free refrigerator?

A

Plate coil evaporator

B

Liquid receiver

C

Oil separator

D

Timer switch

Question 56 1 Marks

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

A

One

B

Two

C

Four

D

Three

Question 57 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 58 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 59 1 Marks

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

A

Refrigeration

B

Ducting system

C

Refrigerant flow

D

Interlocked wiring

Question 60 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 61 1 Marks

What is the effect of improper alignment of machines while installing a central AC plant?

A

Silent operation

B

Excess of wear and tear

C

Less noise and vibration

D

Less power consumption

Question 62 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 63 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 64 1 Marks

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

A

Bimetal thermo

B

Thermostat

C

Relay

D

Timer

Question 65 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 66 1 Marks

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

A

Flush oil particles

B

Charge refrigerant

C

Remove refrigerant

D

Remove moisture and non-condensable

Question 67 1 Marks

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

A

Starting

B

Running

C

Auxiliary

D

Additional

Question 68 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 69 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 70 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 71 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 72 1 Marks

Which material is used for making service valve?

A

Brass

B

Cast iron

C

Aluminium

D

Stainless steel

Question 73 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 74 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 75 1 Marks

What is the advantage of air washer compared to cooling coil of AHU?

A

Faster heat transfer

B

Quick dehumidification

C

No eliminators are required

D

Can be used in small systems

Question 76 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 77 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 78 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 79 1 Marks

Why the capacitor is tested inside a box or case?

A

Explodes safely

B

Erodes the test kit

C

Corrodes the test kit

D

Releases poisonous gas

Question 80 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 81 1 Marks

Which device protects the compressor motor from drawing more current?

A

OLP

B

Relay

C

Thermostat

D

Door switch

Question 82 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 83 1 Marks

Which instrument is used for measuring
heat?

A

Thermometer

B

Anemometer

C

Calorimeter

D

Ammeter

Question 84 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 85 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 86 1 Marks

What is the benefit of VRV system?

A

Bigger in size

B

Many controls

C

Energy saving

D

Saving refrigerant

Question 87 1 Marks

What type of heat is absorbed by primary refrigerant?

A

Total heat

B

Latent heat

C

Specific heat

D

Sensible heat

Question 88 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 89 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 90 1 Marks

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

A

Resistor

B

Thyristor

C

Transistor

D

Thermistor

Question 91 1 Marks

Which type of short cycling is avoided by the design of blower housing in car AC?

A

Oil

B

Air

C

Moisture

D

Lubricant

Question 92 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 93 1 Marks

Which operating condition opens the HPC control switch in car AC?

A

If evaporator pressure exceeds safe limit

B

If there is continuous rain outside

C

If condenser pressure exceeds safe limit

D

If there is continuous air velocity

Question 94 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 95 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 96 1 Marks

Where the air temperature is measured to check the performance of package AC?

A

Supply grille

B

Blower inlet

C

Atmosphere

D

Condenser outlet

Question 97 1 Marks

Which material is used to make ducts in split AC?

A

Thermocole

B

GI sheet

C

Wood

D

Fibre

Question 98 1 Marks

What is the cause of high condensing pressure in water cooled condenser?

A

Lack of lubrication

B

Damage condenser fan

C

Low load on evaporator

D

Defective cooling water pump

Question 99 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 100 1 Marks

Which material is used to make the evaporator of refrigerator?

A

Galvanised iron

B

Stainless steel

C

Aluminium

D

Brass

What is the use of magnetic clutch in Car AC?

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

Which components maintain the pressure difference in RAC system?

Which instrument is used to measure atmospheric pressure?

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

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

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

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

What is the storage capacity of oxygen cylinder?

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

Which refrigerant blend is highly flammable?

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

Why the water flow switch is bypassed to test the HP control switch in package AC?

Which winding has more inductance in refrigerator compressor motor?

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

What parameters are checked if the uneven cooling prevails at different rooms in a chiller plant?

What is meant by total pressure in a duct?

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

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

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

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

What is the minimum cross sectional area of the ducts used with bus AC?

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

What is starving in extinguishing the fire?

What is the temperature maintained in the refrigerator freezer?

What is the purpose of gland packing in water line valves of chiller AC plant?

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

Which material is used for making ICs?

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

Why evaporator of air conditioner has more fins per inch?

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

What is the equivalent of one micron in millimeter?

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

What is the absolute pressure of gas cylinder if the gauge reads 15.3 p.s.i.g?

Which gas is used for flushing blocked capillary tube?

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

Which tool is used to straighten the deformed fins of air cooled condenser?

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

What are the passive components used in electronic circuits?

What is the atmospheric pressure at sea level?

Which parameter of heater element is increased in OLP due to hot compressor dome?

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

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

What is the purpose of using the water cooled condenser in industrial AC plant?

Which switch is interlocked to become on if the power isolator is off in package AC?

Which thermistor s resistance increases if the temperature is decreased?

How to safe guard the hands while handling glass wool?

What is the effect of partially choked thermostatic expansion valve in central AC plant?

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

Why the stainless-steel metal is used to make evaporator in ice plant?

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

What are the causes for blockage in capillary tube?

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

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

Which component is used in frost free refrigerator?

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

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

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

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

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

What is the effect of improper alignment of machines while installing a central AC plant?

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

What is the function of remote control in split AC?

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

What is the advantage of periodical cleaning of air filter?

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

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

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

Which is the numerical designation of ammonia refrigerant?

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

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

Which material is used for making service valve?

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

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

What is the advantage of air washer compared to cooling coil of AHU?

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

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

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

Why the capacitor is tested inside a box or case?

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

What are the passive components used in
electronic circuits?

What is the atmospheric pressure at sea
level?

What are the causes for blockage in
capillary tube?

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

Which instrument is used for measuring
heat?

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