# HPCL Assistant Maintenance Technician Electrical 2019 Solved Question Paper Part One

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Hindustan Petroleum Corporation Limited  (HPCL) Assistant Maintenance Technician Electrical 2019 Solved Question Paper Part One PDF

Here we are providing HPCL assistant maintenance technician electrical solved question paper part one which exam held on 24th April 2019.Next part will be upload tomorrow.

Candidate can download full official question paper and part one solution PDF from post end.

Question-1.The torque to weight ratio of an instrument denotes

A) sensitivity

B) fidelity

C) accuracy

D) selectivity

Solution- Torque/weight ratio an instrument indicates sensitivity. If a pointer is having less weight, it will be having high torque/weight ratio so that even for a very small deflection pointer starts moving and indicates measured value. High torque to weight ratio indicate High sensitivity.

Question-2.The current ‘I’ in the circuit shown in the figure is A) -0.667A

B) 2.667A

C) -2.667A

D) 0.667A

Solution-Assuming current direction and applying KVL

-10+4I+6+2I=0

6I=4

I=4/6=0.667A

Question-3.Watt hour meter is a ……………. Type of instrument

1. A) integrating
2. B) recording
3. C) energy
4. D) indicating

Solution-Integrating instrument are those instrument which measures the total energy supplied by the circuit in a given interval of time. Example-Watt hour meter and Ampere hour meter.

Question-4.The value of voltage drop of an 2 kW electric heater with a resistance of 20Ω is

A) 50V

B)100V

C) 200V

D) 25V

Solution-(P=V²/R)

V²=P.R=2000*20=40000

V=200

Question-5.A 220 V,50 Hz inductive circuit takes a current of 11 A, lagging at 30 .The inductive reactance of the circuit is

A) 20Ω

B) 10 Ω

C) 1 Ω

D) 5 Ω

Solution-Given, V=220, I=11 A, f=50 Hz ,θ=30

Z=V/I=220/11=20 ,

cos=cos 30=√3/2 or R/Z=√3/2 or R=Z*√3/2=20*√3/2=10√3

(XL)²=(Z)²-(R)²=(20)²-(10)²=400-300=100

XL=√100=10

Question-6.What type of material is used to make shunts

A) Manganin

B) Silver

C) Aluminium

D) Copper

Solution-Manganin is used to make shunts.It has zero temperature coefficient of resistance. That means if temp changes then it doesn’t effect on material.

Question-7.The inductive reactance of an inductor is given by

A) Infinity

B) wL

C) zero

D) 1/wL

Solution-Inductive Reactance XL=wL=2πfL

Question-8.In npn transistor , minority carriers are

A) holes

B) acceptor ions

C) free electrons

D) donor ions

Solution-In npn transistor , Minority carriers are holes and majority carriers are electron.

Question-9.The material which is best suited for connecting wires is

A) iron

B) steel

C) copper

D) constantan

Solution-copper wire is best suited for connecting wire,Because is has more ductility ,conductivity,very low resistance.

Question-10.Magneto motive force in a magnetic circuit relates to………… in an electric circuit.

A) potential difference

B) emf

C) electric intensity

D) voltage drop

Solution-mmf of a magnetic circuit is relates to emf of a electric circuit.

Question-11.Which of the following is the least expensive protection for a low voltage system

A) fuse

B) air break CB

C) isolator

D) oil circuit breaker

Solution-Fuse is the least expensive protection for a low voltage system .It is available in the market at very less price to protect the system.

Question-12.A sine wave has a maximum value of 30V .its value at 90 is

A)60V

B)15V

C)0V

D)30V

Solution-v=Vmsinθ=30 sin 90=30V.

Question-13.An alternating voltage is given by v=200 sin314t. Its average value will be

A) 314V

B) 127.4V

C) 100V

D)120V

Solution-Given here , v=200 sin314t

So Vm=200V , Vavg=0.637×200=127.4V

Question-14.The resistance of the earth is

B) 1MΩ

C) 20MΩ

D) infinite

Solution-The resistance of the earth is always taken at very low resistance to pass high value of fault current to ground. So the resistance of the earth is always taken at about zero value.

Question-15.Three -phase wound rotor motors are also regarded as

A) commutator

B) slip ring

C) synchronous motors

D) series

Solution-Three phase wound rotor is always known as slip ring type induction motors  Here three slip ring is used to add external resistors in star connection ,by adding this we can change the torque of IM.

Question-16.The unit of charge is

A) volts

B) ampere

C) ampere hour

D) coulomb

Solution-The unit of charge is Coulomb,denoted by ‘C’.

Question-17.A circuit has inductance of 4H .If the circuit current changes at the rate of 5 A/s ,then the self -induced emf is

A)5/4V

B)20V

C)4/5V

D)25V

Solution-VL=L×di/dt=4×5=20V

Question-18.In order to obtain higher efficiency for three-phase induction motor ,its slip should be

A) high

B) very low

C) 1

D) very low

Solution-The efficiency of three phase induction motor

=Pg(1-s)/Pg=1-s

Here if value of ‘s’ is kept at very low value then (1-s) difference is value is very high ,then efficiency value of directly proportional to (1-s).then we obtained higher value of efficiency.

Question-19.The slip of a three-phase induction motor when its rotor is blocked will be

A) 0.5

B) zero

C) 1

D) 0.1

Solution-At starting or when motor rotor blocked then slip of a three phase IM is highest or its value is equal to 1.

Question-20.The most commonly used induction type instrument is

A) induction wattmeter

B) induction watt-hour meter

C) induction ammeter

D) induction voltmeter

Solution-Induction type instrument is most commonly used instrument .which is generally installed  in every house or building to measure or record energy consumed at particular time period.

Question-21.If a 4 pole induction motor has a synchronous speed of 1800 rpm ,then the supply frequency is

A) 25 Hz

B) 60 Hz

C) 0 Hz

D) 50 Hz

Solution-Given, P=4 , Ns=1800 rpm

f=Ns×P/120=1800×4/120=60 Hz.

Question-22.Merz price protection system is employed for the protection of

A) alternators

B) thunder

C) transmission line

D) lightning

Solution- Merz price protection system is employed for the protection of Alternator or transformer .It is used for earth fault or phase fault protection (internal fault only).

Question-23.The type of plant which incurs maximum capital cost is

A) steam

B) nuclear

C) diesel

D) hydro

Solution-Nuclear power plant has maximum capital cost,because its installation cost is very high,for repairing and maintenance or operation  it needs highly skilled person.

Question-24.An alternating voltage is given by v=10 sin 157t. The frequency of the alternating is

A) 50 Hz

B) 15 Hz

C) 25 Hz

D) 60Hz

Solution- In given equation ,v=10 sin 157t

Here Wt=157t=2πf=157

So, f=157/2π=25 Hz

Question-25.The pointer of an indicating instrument is of

A) aluminium

B) iron

C) steel

D) silver