- Technical Blog From My Notebook

## Junior Instructor Electrician Previous Question paper

In this post, the Previous Question paper of Junior Instructor Electrician (Category Code: 726/2014) is given. The PDF can be downloaded at the last. You can watch the Detailed explanations in EEE Mae Easy Youtube Channel.

The first 20 questions are removed as they were related to GK, Current Affairs and Renaissance. There will not be the GK section in any of the Technical Exams.

A:-165 A/sq. cm
B:-118 A/sq. cm
C:-178 A/sq. cm
D:-135 A/sq. cm

#### In which type of winding, a long coil of sufficient length is firs wound and then inserted in one slot and the remainder of the length is turned and inserted in the adjacent slots?

A:-Skein winding
B:-Involute coil winding
C:-Chain winding

#### Question23:-If single phasing occurs during the running of a 3 phase induction motor, then

A:-the motor may or may not run, will draw large current and the winding may burnout
B:-the motor may or may not run, will draw the normal current
C:-the motor will run normally
D:-the motor will stop

A:-oil pressure
B:-gas pressure
C:-temperature
D:-current

### Question25:-

#### The cooling oil used in a transformer should have

A:-to absorb moisture easily when exposed to air
B:-high insulation resistance
C:-low heat conductivity
D:-low firing point

#### (adsbygoogle = window.adsbygoogle || []).push({}); Question26:-The maximum value of torque that a synchronous motor can develop without losing its synchronism is known as

A:-breaking torque
B:-synchronising torque
C:-pull out torque
D:-pull in torque

#### Question27:-The transformer whose secondary is not isolated from the primary is

A:-current transformer
B:-potential transformer
C:-autotransformer
D:-step up transformer

A:-1000 rpm
B:-1500 rpm
C:-750 rpm
D:-160 rpm

#### Question29:-The light meter measures

A:-luminance
B:-luminous intensity
C:-luminous flux
D:-illuminance

#### Question30:-A servo voltage stabilizer provides a constant voltage to an accuracy around

A:-±1% to ±0.5%
B:-0 to ±1%
C:-±0.5% to ±1.5%
D:-±1% to ±1.5%

### Question31:-

Submersible pumps come under the category of
A:-centrifugal pumps
B:-jet pumps
C:-reciprocating pumps
D:-mono bloc pumps

#### Question32:-The size of the transformer used in the battery charger depends upon

A:-charging voltage of the battery
B:-charging power of the battery
C:-charging current capacity
D:-charging energy of the battery

A:-91.44 cm
B:-9.144 cm
C:-91.44 mm
D:-9.144 mm

A:-30 W
B:-60 W
C:-80 W
D:-125 W

A:-2 sq.mm
B:-1.5 sq.mm
C:-2.5 sq.mm
D:-1 sq.mm

### The fusible plug fitted on the top of the electrical geyser casing is to

A:-disconnect the electrical supply in case of short circuit
B:-release the pressure inside the tank in case of thermostat failure
C:-fuse and release the steam inside the heater in case of overheat
D:-eject the 3 pin plug to disconnect the supply in case of earth fault

#### Question38:-

The heat generated in a conductor by the flow of an electric current is proportional to the square of the current value, the resistance of the conductor and the time for which the current flows. This is stated by the law
A:-Ohm's law
B:-Joule's law
D:-Murphy's law

#### Question39:-In the case of double squirrel cage induction motors, the outer cage has

A:-high resistance and low reactance
B:-high resistance and high reactance
C:-low resistance and high reactance
D:-low resistance and low reactance

#### Question40:-The property retentivity of material is useful on the construction of

A:-transformers
B:-electromagnets
C:-permanent magnets
D:-non magnetic substances

#### Question41:-The leakage flux in a transformer depends upon

A:-load current, voltage, frequency and power factor

#### Question42:-

The slip rings of wound rotor machines are made from
A:-mild steel
B:-copper
C:-brass
D:-cast iron

#### Question43:-In large generators, Hydrogen is used as

A:-conducting medium
B:-insulating medium
C:-insulating and cooling medium
D:-conducting and cooling medium

#### Question44:-Highest power factor can be expected in which method of heating?

A:-Electric arc heating
B:-Dielectric heating
C:-Induction heating
D:-Resistance heating

#### Question45:-Sulpher hexafluoride is used in

A:-Dynamos
B:-DC series motors
C:-Switch gears
D:-Synchronous motors

#### Question46:-In an automobile electrical system, where alternators are used as a power source, the negative terminal is earthed, because

A:-to reduce corrosion
B:-to prevent damage to rectifiers and transistors
C:-to avoid electric shock
D:-to avoid damage to the alternator

#### Question47:-Magnetic overload relays operate faster than bi-metallic relays because magnetic overload relays operate on

A:-current intensity
B:-voltage intensity
C:-thermal intensity
D:-power factor

#### Question48:-3 phase squirrel cage induction motors with high slip, high starting torque and relatively low starting current are coming under the class of

A:-Class D motors
B:-Class C motors
C:-Class B motors
D:-Class A motors

A:-1.0
B:-0.3
C:-0.5
D:-1.5

#### (adsbygoogle = window.adsbygoogle || []).push({}); Question50:-A triac, when tested by an ohmmeter, will show a lower resistance in the order of 300 ohms between terminals

A:-MT 2 positive and G negative
B:-MT 1 positive and G negative
C:-MT 2 negative and G positive
D:-MT 1 positive and MT 2 negative

#### Question51:-_________ is the measure of how much potential difference the insulation layer can withstand without breaking down.

A:-Insulation resistance
B:-Breakdown voltage
C:-Resistance
D:-Dielectric strength

#### Question52:-The light output of Tin oxide Sodium lamps is in the order of

A:-50 lumens/watt
B:-45 lumens/watt
C:-75 lumens/watt
D:-150 lumens/watt

#### Question53:-The torque of a three-phase induction motor is proportional to

A:-square root of the applied voltage
B:-applied voltage
C:-square of the applied voltage
D:-half of the applied voltage

#### Question54:-Tap changing transformers are used for

A:-stepping up the voltage
B:-stepping down the voltage
C:-both stepping up and stepping down the voltage
D:-supplying low current for instruments

#### Question55:-Which Dc motor has a negligible effect on the speed with an increase in torque?

A:-DC differential compound motor
B:-DC cumulative compound motor
C:-DC series motor
D:-DC shunt motor

#### Question56:-In a pure inductive AC circuit, the average true power is equal to

A:-V x I watts
B:-Zero watts
C:-Square of current multiplied by reactance Watts
D:-V x I volt-amperes

#### Question57:-The part of an instrument which helps in leading in and leading out the current to the moving coil is

A:-the spindle
B:-the copper or aluminium disc
C:-jewel bearing
D:-control spring

A:-±0.1mm
B:-±0.5mm
C:-±0.001mm
D:-±0.01mm

#### Question59:-When a secondary battery is charged at 2% to 3% of normal rate for a long period, it is known as

A:-boost charge
B:-trickle charge
C:-freshening charge
D:-initial charge

#### Question60:-Double squirrel cage induction motors are used where ________ torque is essential.

A:-high starting torque
B:-low starting torque
C:-low running torque
D:-high running torque

A:-Corridor wiring
B:-Tunnel wiring
C:-Godown wiring
D:-Bank wiring

A:-coil pitch
B:-winding pitch
C:-pole pitch
D:-pitch factor

A:-5%
B:-10%
C:-3%
D:-20%

A:-3187 joule
B:-4187 joule
C:-4187 calorie
D:-3187 calorie

A:-resistance
B:-conductance
C:-reactance
D:-impedance

#### Question66:-The damping winding in a synchronous motor is generally used

A:-to provide starting torque only
B:-to reduce the noise level
C:-to prevent hunting and to provide the starting torque
D:-to reduce eddy currents

#### Question67:-Voltage-dependent resistors are used as

A:-as current stabilizers
B:-as heating elements
C:-to suppress surges
D:-for inductive circuits

#### Question68:-In a DC generator, brush shifting is done to

A:-alter the inter pole flux
B:-alter the main field flux
C:-neutralise the cross magnetizing effect
D:-neutralise the demagnetizing effect

#### Question69:-To control a lamp from 4 positions, how many switches are required?

A:-4 two-way switches
B:-4 intermediate switches
C:-3 two-way switches and one intermediate switch
D:-2 intermediate switches and 2 two-way switches

### Question70:-The fusing factor for HRC fuse is

A:-2.0
B:-1.7
C:-1.4
D:-1.1

A:-0.75m
B:-0.9m
C:-1.0m
D:-1.05m

A:-5.791m
B:-6.096m
C:-5.486m
D:-4.572m

#### Question73:-In capacitor start, capacitor run motors, the capacitors used are

A:-both capacitors are of the same value
B:-one larger value capacitor of oil-filled type and a smaller value capacitor of electrolytic type.
C:-one larger value capacitor of electrolytic type and a smaller value capacitor of oil-filled type.
D:-both capacitors are of an electrolytic type.

A:-1/6
B:-1/5
C:-1/4
D:-1/7

#### Question75:-In an AC operated relay, the purpose of shading coil placed near the tip of magnetic pole face is to

A:-eliminate chatter
B:-eliminate humming
C:-to reduce eddy current
D:-to reduce hysteresis loss

#### Question76:-To test an armature for the short-circuited coils, ________ is used along with the growler.

A:-milli-voltmeter
C:-ohm meter
D:-meggar

#### Question77:-The type of fire extinguisher used where liquified gas is on fire is

A:-water filled fire extinguisher
B:-dry powder extinguisher
C:-foam type fire extinguisher
D:-carbon dioxide fire extinguisher

#### Question78:-Earthing one of the wires of electrical system, to limit the maximum voltage to earth under normal operating conditions is known as

A:-equipment earthing
B:-system earthing
C:-generator earthing
D:-substation earthing

#### Question79:-To measure the earth electrode resistance, the current and pressure spikes of the earth resistance tester are to be driven into the ground at a distance of ______ from the main electrode under test.

A:-20m and 10m apart respectively
B:-25m and 12.5m apart respectively
C:-20m and 10m apart respectively in a straight line
D:-25m and 12.5m apart respectively in a straight line.

#### Question80:-The type of joint used for overhead lines for tapping the electrical energy perpendicular to the service line is

A:-knotted tap joint
B:-aerial tap joint
C:-tee joint
D:-Britannia tee joint

A:-2.5m
B:-2.75m
C:-2.25m
D:-2.4m

#### Question82:-If firing angle in an SCR rectifier is increased, the output is

A:-remains same
B:-SCR is turned off
C:-decreased
D:-increased

#### Question83:-Which electrode of the CRT mainly controls the brightness of the image on the screen?

A:-Anode
B:-Cathode
C:-Control grid
D:-Focusing electrodes

#### Question84:-The efficiency of a transformer is maximum, when

B:-hysteresis loss is equal to eddy current loss
C:-copper loss is equal to eddy current loss
D:-copper loss is equal to iron loss

#### Question85:-For the parallel operation of two transformers, the phase sequence must be identical, otherwise, during the cycle

B:-impossible to take the full load output without excessive heating of one of the transformer
C:-each pair of phases will be open-circuited
D:-each pair of phases will be short-circuited

A:-32
B:-16
C:-8
D:-4

A:-155°C
B:-130°C
C:-120°C
D:-180°C

#### Question88:-The ratio of the intensity of magnetization to the magnetizing force is known as

A:-permeability
B:-permittivity
C:-susceptibility
D:-magnetic potential

#### Question89:-While testing the field coil connections by compass method, the DC voltage to be applied to the field coil is

A:-10 to 20% of rated voltage
B:-the rated voltage
C:-60 to 70% of rated voltage
D:-200% of rated voltage

#### (adsbygoogle = window.adsbygoogle || []).push({}); Question90:-The relays which are capable of maintaining their contacts in the last assumed position after the power is cut off are

A:-latching relays
B:-thermal relays
C:-reed relays
D:-electro-mechanical relays

### Question91:-In large motor-generator sets, the AC motor used is usually

A:-squirrel cage type induction motor
B:-wound rotor type induction motor
C:-synchronous motor
D:-universal motor

### Question92:-A wattmeter measures the

A:-Apparent power
B:-Active power
C:-Reactive power
D:-Power factor

A:-voltage
B:-current
C:-power factor
D:-frequency

A:-unity
B:-zero
C:-more than 0.5
D:-less than 0.5

#### (adsbygoogle = window.adsbygoogle || []).push({}); Question95:-A moving coil milliammeter having a resistance of 10 ohm gives full scale deflection, when a current of 5mA is passed through it. If the instrument to be used to measure a current up to 1A, then

A:-a resistance of 0.502 ohm must be connected in series with the ammeter
B:-a resistance of 0.502 ohm must be connected in series with the load
C:-a resistance of 0.502 ohm must be connected in parallel to the ammeter
D:-a resistance of 0.502 ohm mus be connected in parallel to the load

#### Question96:-The instrument which give the value of the quantity to be measured in terms of deflection and instrument constants are

A:-secondary instruments
B:-indicating instruments
C:-integrating instruments
D:-absolute instruments

#### Question97:-A measuring instrument is enclosed inside an iron case. This is for protecting the measuring mechanism from

A:-heat
B:-magnetic flux
C:-static electricity
D:-hysteresis effect

A:-2.1 to 2.6V
B:-2.5 to 3.6V
C:-1.2 to 1.4 V
D:-1.5V

#### Question99:-The illumination is directly proportional to the cosine of the angle made by the normal to the illuminated surface with the direction of the incident flux. This statement is associated with

A:-Macbeth's law of illumination
B:-Bunsen's law of illumination
C:-Lambert's cosine law
D:-Plank's law