# ELECTRICAL 70 IMPORTANT MCQ PDF FOR VIZAG MT & MPVYAPAM SUB ENGINEER EXAM 2017

1.Charge on an electron is ?

a) 1.602
* 10-19 C.         b) 1.602
* 10-19 μC.
c) 9.107
* 10-31 C.         d) 9.107
* 10-25 C.
ANS: (a)
2) An electron having mass ‘m’ kg and charge ‘e’ columb travels
from rest through a potential difference of ‘V’ volts. It has a kinetic energy
of ?
a) mV
joules
b) m  eV joules
c) eV
joules
d) m/e  joules
ANS: (c)
3) A current is said to be direct current when its ?
a)
magnitude remains constant with time
b)
magnitude changes with time
c)
direction changes with time
d)
magnitude and direction changes with time
ANS: (a)
4) A current is said to be alternating when it changes in ?
a)
magnitude only

b) direction only
c) both
magnitude and direction      d) none
ANS: (c)
5) The generator develops an electric pressure by ?
a)
conversion of
heat
b) conversion of light
c)
electro-magnetic
induction            d)
conversion of chemical energy
ANS: (c)
6) The dc generator works on the principle of ?
a)
Fleming’s left hand rule
b)
Fleming’s right hand rule
c)
Lenz’s
law
d) none of the above
ANS: (b)
7) The basic function of a transformer is to change ?
a) level
of the
voltage
b) the power level
c) the
power
factor
d)  the frequency
ANS: (a)
8) Transformer is used ?
a) to
step-up the voltage
b) to step-down the voltage
c) on
d.c             d)
to step-up or step-down the voltage
ANS: (d)
9) An electron device means the device in which the conduction of
electrons takes place through ?
a) a
gas    b) vaccum     c) a semi-conductor
d) a
gas, semi-conductor or vaccum
ANS: (d)
10) Which of the following is used as a passive component in an
electronic circuit ?
a)
vaccum
diode
b) Zener diode
c)
inductor
d) SCR
ANS: C
11) Which is a conventional source of energy ?
a) solar
c)
geothermal  d) wind
ANS: (b)
12) The disadvantages of renewable source of energy is/are ?
a)
intermittency
b) lack of dependability
c)
availability in low energy densities   d) all the abaove
ANS: (d)
13) Transmission lines connect ?
a)
generating station to a switching station / step down transformer station.
b) step
down transformer station to service transformer banks
c)
distribution transformer to consumer premises
d)
service points to consumer premises
ANS: (a)
14) A 3-phase 4-wire system is commonly used for ?
a)
primary
distribution
b) secondary distribution
c)
primary
transmission
d) secondary transmission
ANS: (b)
15 ) The basic elements of an electric drive are :
a)
electric motor and the transmission system
b)
electric motor ,the transmission and control system
c) the
transmission and control system
d)
electric motor and conversion equipment
ANS: (b)
16) The main draw back of electric drive is that:
a) it is
cumbersome drive
b) it is
costlier in intial as well as in maintenance cost
c)
electric power supply failure makes the drive standstill
d) all
of the above.
ANS: (c)
17) The absolute measurement of resistance involves the
measurement of ?
a)
length and time           b)
length and mass
c)
velocity
d) either a or c
ANS : (d)
18 ) For absolute measurement of current the method commonly used
is ?
a)
electro-dynamometer method
b)
tangent galvanometer method
c)
Rayleigh current balance method
d)
Lorenz method
ANS: (c)
19) Any physical system which does not automatically correct for
variation in its output, is called ?
a) open
loop system
b)
closed loop system
c) unstable
system
d) none
of the above
ANS:(a)
20) open loop control system is one in which the control action ?
a)
depends on the input signal
b) is
independent of the desired output
c)
depends on system variables
d)
depends on system size
ANS:(b)
21.The flow of electrical current in a conductor is due to flow
of  ?
a)
electrons.         b) protons.
c)
electrons and ions.         d) charged
particles.
ANS: (a)
22) An electric current is the ?
a)
random movement of electrons in a conductor
b)
movement of free electrons predominately in one direction
c)
pressure difference between two poles
d) the
power that causes drift of electrons.
ANS: (b)
23)The direction of current in an ac circuit ?
a) is
from positive to negative.
b) is
always in one direction.
c)
varies from instant to instant.
d)
cannot be determined.
ANS: (c)
24) When an electric current is passed through a bucket full of
water, lot of bubbling in there–the electric current is ?
a) ac.

b) dc.
c)
pulsating.
d)
none
ANS: (b)
25) Which device illustrates the principle of electro-mechanical
conversion ? (asked in B.T.E M.P 1996)
a)
Amplifier.

b)Battery charger.
c)
Transformer.

d) Electric bell.
ANS: (a)
26) Fleming’s left hand rule is applicable to ?
a) dc
generator
b) dc motor
c)
alternator

d) Transformer
ANS: (b)
27) In a transformer electrical power is transferred from one
circuit to another with out change in ?
a)
voltage
b) current
c)
frequency

d)  turns
ANS: (C)
28) The frequency of a voltage at the secondary is ?
a)
greater than that of primary
b) equal to that of primary
c) less
than that of primary

d) none
ANS: (b)
29) An example of solid state device is  ?
a) zener
diode    b) triode     c) pentode
d)
thyratron
ANS: (a)
30) Ratings on a capacitor are given 25μF , 12V. Also a plus sign
is written near one of its terminals. The capacitor is  ?
a) mica
capacitor

b) ceramic capacitor
c)electrolytic capacitor    d) paper capacitor
ANS: (C)
31) Which of the following power plants is the least reliable ?
a) wind

b) tidal
c)
geothermal            d)
solor
ANS: (a)
32) Which of the following power plants is the most reliable ?
a)
diesel

b) Hydro-electric
c) steam

d) tidal
ANS: (b)
POWER SYSTEMS
33) Which of the following is usually not the generating voltage ?
a) 6.6
KV
b) 11 KV
c) 12.5
KV
d) 13.2
KV
ANS: (c)
34) The highest transmission voltage in india is ?
a) 750
KV

b) 400 KV
c) 220
KV

d) 132 KV
ANS: (b)
35 ) DC motors are still preferred for use in ?
a)
electric excavators  steel mills and cranes
b)
lathes and machine tools
c) flour
mills and jaw crushers
d) paper
industry
ANS: (a)
36) The  conversion of AC into DC can be affected by the use
of ?
a)
motor-generator set
b)
mercury arc rectifier
c) silicon
diodes
d) any
of the above.
ANS: (d)
37) Zener diodes , when used as voltage standards ?
a) are
forward biased           b) are
reverse biased
c) cover
a wide range of current

d) operate in breakdown strength
e) all
of above except (a)
ANS : (e)
38 ) The material to be used in the manufacture of a standard
resistor should be of ?
a) low
resistivity
b) high
resistivity and low temparature co-efficient
c) high
temp co-efficient
d) low
resistivity and high temparature co-efficient
ANS: (b)
39) Basic elements of a closed loop control system are the ?
a)
feedback and controlled system
b)
controller and controlled system
c)
controlled system and servo system
d) feed
back element and controlled system and controller
ANS:(d)
40) A closed loop control system is basically different from open
loop control system due to ?
a)
feedback
b)
servomechanism
c)
actuating signal
d) error
signal
ANS:(a)
41.Speed of the stator field of an Induction motor is
(a) Synchronous speed
(b) Any speed
(c) Less than Synchronous
(d) Slip Speed
Ans(a)
Synchronous speed
42.Difference in speed between stator field and rotor
(c)Slip
(d) Regulation
Ans:(c)Slip
43.Frequency of current in rotor
(a)Supply frequency
(b)Less than supply frequency
(c)Greater than supply frequency
(d)Slip frequency
Ans;(d) Slip Frequency
44. Shape of the torque slip curve is
(a) Rectangular Hyperbola
(b)Parabola
(c)Sine
(d) Cosine
Ans;(a)
Rectangular Hyperbola
45.Machine with negative slip
(a)Induction Motor
(b) Brake
(c)Induction Generator
(d)Synchronous machine
Ans(c)
Induction Generator

46.When
rotor is at standstill

(a)slip is zero
(b)slip is one
(c)Any slip
(d)Slip is infinity
Ans;(b)Slip
is one
47.When the motor runs at synchronous speed slip is
(a) One
(b) Infinity
(c)Zero
(d)Two
Ans:(c)Zero
48.Which torque is greater
(a)Break down
(d) Running
Ans:(a)
Break down

49.An
Induction motor is analogous to

(a)DC motor
(b)Transformer
(c)Synchronous motor
(d) DC Generator
Ans:(b)Transformer
50.Blocked
rotor test is analogous to

(a) SC test
(b)OC test
(c)Swinburnes
Ans:(a)SC
test
51.No load test is analogous to
(a) SC test
(c)OC test
(d)Swinburnes test
Ans:(c)OC
test
52.Rotor Copper loss is equal to
(a)Friction loss
(b)Stator loss
(c)slip times rotor input
(d)rotational loss
Ans:
(c)slip times rotor input
53.For the purpose of plugging
(a)N is positive w.r.t to Ns
(b)N is zero
(c)N is infinity
(d)N is negative w.r.t to Ns
Ans: (d)N
is negative w.r.t to Ns
54.Parameter from no load test is
(a)Ri and Xi
(b)Ro and Xo
(c) Copper loss
(d)Impedance
Ans:(b)Ro
and Xo
55.If stator field is rotating in clockwise direction rotor
rotates in

(a) Any direction
(b)Cannot predict
(c)Anticlockwise
(d) clockwise
Ans:
(d)clockwise
66.Blocked rotor test is conducted at
(a)High voltage
(b)Rated current
(c)High current
(d)Rated voltage
Ans(b)Rated
current
67.Speed of rotor field in space
(a)N
(b)Any speed
(c)Ns
(d)Slip speed
Ans(c)Ns
68.Line joining tangent and output line in a circle diagram gives
(a)Cu loss
(b)Stator loss
(c)Maximum output
(d)Maximum Torque
Ans;(c)maximum
Output
69..Line joining tangent and Torque line in a circle diagram gives
(a)Cu loss
(b)Stator loss
(c)Maximum output
(d)Maximum Torque
Ans;(d)maximum
Torque