Mock Test: SSC JE (ME)- 15

QUESTION: 1

For a single phase capacitor start induction motor which of the following is valid ?

A.
rotation can be changed by reversing main winding terminals
B.
direction of rotation can be changed
C.
rotation can be changed by interchanging supply terminals
D.
None of these

Solution:

QUESTION: 2

To avoid arcing, connect suitable value of in earthing

A.
capacitance
B.
inductance
C.
resistance
D.
susceptance

Solution:

QUESTION: 3

What is the value of the current I in the circuit shown below ?

A.
20 A
B.
25 A
C.
30 A
D.
36 A

Solution:

QUESTION: 4

In the following type of conductors the corona is minimum in

A.
circular
B.
stranded
C.
helical
D.
rectangular

Solution:

QUESTION: 5

Consider the following w.r.t. the circuit as shown below

1. V_R 100√ 2V=
2. | I |rms = 2A
3. L = 0.25H
Which of the above statements is/are correct?

A.
1 only
B.
2 and 3
C.
1 and 3
D.
1 and 2

Solution:

QUESTION: 6

If the time delay of relay with TMS setting 0.1 is 10 second then what is the time delay whenthe TMS setting is changed to 0.5

A.
2 sec
B.
20 sec
C.
100 sec
D.
50 sec

Solution:

QUESTION: 7

The machine used in wind will is

A.
Alternator
B.
Induction generator
C.
synchronous generator
D.
All of these

Solution:

QUESTION: 8

In an RLC series resonant circuit, if the maximum stored energy is increased by 10%and at the same time, the energy dissipated per cycle is reduced by 10%, it will result in whichone of the following ?

A.
An 11% decrease in quality factor
B.
An increase in the resonant frequency by 11%
C.
A 22% increase in quality factor
D.
A decrease in the resonance frequency by 22%

Solution:

QUESTION: 9

Consider the following components Out of these components, which component(s)can be common for primary & back up protection

A.
CB's
B.
CTs
C.
Battery room
D.
Equipment to be protected

Solution:

QUESTION: 10

In a series resonance circuit, at resonance selectivity Q is equal to

A.
B.
C.
D.

Solution:

QUESTION: 11

Positive sequence terminal voltage is zero in

A.
L–L
B.
L–L–G
C.
L–G
D.
L–L–L

Solution:

QUESTION: 12

.Most economical load in the underground cable is

A.
less than the surge impedance
B.
equal to the surge impedance
C.
more than surge impedance
D.
any load

Solution:

QUESTION: 13

The friction experienced by a body, when in motion, is known as

A.
rolling friction
B.
dynamic friction
C.
limiting friction
D.
static friction

Solution:

QUESTION: 14

certain network consist of a large number of ideal linear resistances, one of which is
designated consumed by R is P1 when only the first source is active, and P2 when only the
second source is active, if both source are active simultaneously, then the power consumed by R
is

A.
P1 + P2
B.
C.
D.

Solution:

QUESTION: 15

Consider the following statement about D'Arsonval Movement
1. It is best suited for d.c. current measurement
2. It responds to the average value of current
3. It could be used for power measurements Which of these statements is/are correct

A.
only 1
B.
1 and 2
C.
2 and 3
D.
1, 2, 3 and 4

Solution:

QUESTION: 16

Torque/weight ratio of an instrument indicates

A.
selectivity
B.
accuracy
C.
fidelity
D.
sensitivity

Solution:

QUESTION: 17

A current transformer has a phase error of +3º. The phase angle between the primary andsecondary current is

A.
3º
B.
177º
C.
180º
D.
183º

Solution:

QUESTION: 18

The direction of rotation of a d.c. series motorcan be reversed

A.
by interchanging supply terminals
B.
by interchanging the field terminals
C.
either by interchanging supply terminals or by interchanging field terminals
D.
by interchanging supply terminals as well as field terminals

Solution:

QUESTION: 19

A three phase transformer having zero sequence impedance of Zo has the zero-sequencenetwork as shown in the figure below. The connection of its windings are

A.
star-star
B.
delta-delta
C.
stat-delta
D.
delta-star with neutral

Solution:

QUESTION: 20

The transformer laminations are insulated from each other by

A.
mica strip
B.
thin coat of varnish
C.
paper
D.
any of the above

Solution:

QUESTION: 21

A coil with certain number of turns has a specified time constant. If the no. of turns isdoubled, its time constant would

A.
remain unaffected
B.
becomes doubled
C.
becomes four fold
D.
get halved

Solution:

QUESTION: 22

The technique of adding a precise amount of time between the trigger point and the beginningof the scope-sweep in a CRO is known as

A.
Free running sweep
B.
Delayed sweep
C.
Triggered sweep
D.
Non-sawtooth sweep

Solution:

QUESTION: 23

In a CE (common emitter) transistor, V_CC = 12V and the zero signal collector current is 1mA. Determine the operating point when collector load (R_C) is 6 KW

A.
6V, 1mA
B.
6V, 2mA
C.
12V, 1mA
D.
12V, 2mA

Solution:

QUESTION: 24

A 100 H.P. motor with a synchronous speed of 720 rpm at 50 Hz has 96 stator slots with4 conductors per slot and 120 rotor slots with 2 conductors per slot. If the full load efficiencyis 0.92 and the p.f. is 0.9 lagging, the current per phase when the stator is star connected to3-phase, 500V supply will be

A.
54 A
B.
67 A
C.
85 A
D.
104 A

Solution:

QUESTION: 25

Which of the following application requires high starting torque ?

A.
lathe machines
B.
centrifugal pump
C.
locomotive
D.
air blower

Solution:

QUESTION: 26

Which DC motor will be preferred for machine tools ?

A.
series motor
B.
shunt motor
C.
cumulative compound motor
D.
differentially compound motor

Solution:

QUESTION: 27

The empty space between the plates of a capacitor is filled with liquid of dielectricconstant K the capacitance of capacitor

A.
Decreases by a factor K
B.
Increases by a factor K
C.
increases by a factor K²
D.
decreases by a factor K²

Solution:

QUESTION: 28

If current through the operating coil of a moving iron instrument is doubled, the operating forcebecomes

A.
two times
B.
four times
C.
three times
D.
one-half time

Solution:

QUESTION: 29

A magnetic needle is kept in a uniform magnetic field. It experiences

A.
A force and a torque
B.
A force and not a torque
C.
A torque but not a force
D.
None of these

Solution:

QUESTION: 30

Disadvantage of low p.f. is

A.
greater conductor size
B.
large copper loss
C.
poor voltage regulation
D.
all of the above

Solution:

QUESTION: 31

For improvement of power factor

A.
capacitor is used in parallel
B.
inductor is used in parallel
C.
capacitor is used in series
D.
both capacitor and inductor are used in parallel

Solution:

QUESTION: 32

A 4-pole 500V shunt motor has 720 wave connected conductors on its armature. The fullload armature current is 60A and flux per pole is 0.03 Wb. The armature resistance is 0.2Wand the contact drop per brush is 1V. What is the back emf ?

A.
490V
B.
460V
C.
445V
D.
486V

Solution:

QUESTION: 33

In an autotransformer of voltage ratio the fraction of power transferred
inductively is proportional to

A.
B.
C.
D.

Solution:

QUESTION: 34

Stepped core is used in transformers in order to reduce

A.
volume of iron
B.
volume of copper
C.
iron loss
D.
reluctance of core

Solution:

QUESTION: 35

A make break switch is provided to disconnect the battery when the meter is not in use is

A.
both series and shunt type ohm meters
B.
only in series type ohm meters
C.
only in shunt type ohm meters
D.
none of the above

Solution:

QUESTION: 36

Which instrument is the cheapest, disregarding the accuracy

A.
PMMC
B.
Moving Iron
C.
Electrodynamometer
D.
Rectifier

Solution:

QUESTION: 37

In dc machines, the armature reaction mmf is

A.
stationary w.r.t. armature
B.
rotating w.r.t. stator
C.
stationary w.r.t. stator
D.
rotating w.r.t. brushes

Solution:

QUESTION: 38

Inductance affects the flow of direct current at the time of

A.
turning off
B.
turning on
C.
turning on and off
D.
none of these

Solution:

QUESTION: 39

A centre zero ohmmeter connected in the rotor circuit of 6-pole 50 Hz induction motor makes30 oscillations in one minutes. The rotor speed is

A.
970
B.
990
C.
1010
D.
1030

Solution:

QUESTION: 40

A coil of resistance 20W and inductance 0.8 H is connected to a 200V DC supply. The rate
of change of current at t = 0+ is

A.
B.
C.
D.

Solution:

QUESTION: 41

What should be the value of resistance R, in the above circuit if it has to absorb the maximum
power from the source

A.
B.
C.
D.

Solution:

QUESTION: 42

The torque on the rotor of a 3- W motor is more constant than that of a single phase motorbecause

A.
single phase motor are small in size
B.
single phase motor are not self starting
C.
Three phase power is of constant value
D.
None of these

Solution:

QUESTION: 43

When the secondary coil of a transformer is short circuited, the primary inductance

A.
remains unchanged
B.
is increased
C.
is decreased
D.
none of these

Solution:

QUESTION: 44

Q-factor of a parallel tuned circuit can be increased by

A.
increasing circuit resistance
B.
decreasing circuit resistance
C.
decreasing inductance of the circuit
D.
none of these

Solution:

QUESTION: 45

Air blast circuit breakers for 400 KV power system are designed to operate in

A.
100 micro-second
B.
50 milli second
C.
0-5 second
D.
0.1 second

Solution:

QUESTION: 46

An overhead line conductor has an inductance per unit length of L Henry. If the entire medium
around the conductor is filled with a dielectric material of permittivity (E), then the inductance
will be

A.
B.
C.
L
D.
Unchanged

Solution:

QUESTION: 47

In two-wattmeter method of power measurement one of the wattmeter will shownegative reading when the load pf angle is strictly

A.
less than 30º
B.
less than 60º
C.
greater than 30º
D.
greater than 60º

Solution:

QUESTION: 48

A reactance relay is

A.
voltage restrained over current relay
B.
directional restrained over current relay
C.
voltage restrained directional relay
D.
none of above

Solution:

QUESTION: 49

To limit current chopping in vacuum circuit breakers, the contact

A.
high vapour pressure and low conductivity properties
B.
low vapour pressure and low conductivity properties
C.
high vapour pressure and high conductivity properties
D.
low vapour pressure and high conductivity properties

Solution:

QUESTION: 50

The main difference between speed-time curves of mainline service as compared to suburbanservices in

A.
longer free running periods
B.
longer coasting periods
C.
shorter acceleration and braking periods
D.
all of the above

Solution:

QUESTION: 51

Which of the following relay has directional feature

A.
Z-relay
B.
X-relay
C.
MHO-relay
D.
None of these

Solution:

QUESTION: 52

Carbon brushes are preferable to copper brushes because

A.
they have longer life
B.
they reduce armature reaction
C.
they have lower resistance
D.
they reduce sparking

Solution:

QUESTION: 53

A power plant has a maximum demand of 15 MW. The load factor is 50% and the plantfactor is 40%. The operating reserve is

A.
3.0 MW
B.
3.75 MW
C.
6.0 MW
D.
7.5 MW

Solution:

QUESTION: 54

The starting torque of a servomotor under unbalanced operation is proportional to

A.
I_a
B.
I²_a
C.
D.

Solution:

QUESTION: 55

Quadrilateral speed-time curve is the closer approximation for

A.
main line service
B.
suburban service
C.
urban service
D.
urban & suburban service

Solution:

QUESTION: 56

Travelling crane is used for lifting and moving heavy loads. It uses

A.
series wound DC motor
B.
induction motor
C.
synchronous motor
D.
shunt motor

Solution:

QUESTION: 57

For Domestic wiring method commonly used is

A.
Radial system
B.
Ring-Main system
C.
Series system
D.
None of these

Solution:

QUESTION: 58

The time taken for a surge to travel a 600 km long overhead transmission link is

A.
6s
B.
2s
C.
0.02s
D.
0.002s

Solution:

QUESTION: 59

Ripple factor of half wave rectifier is

A.
1.21
B.
1.11
C.
1.1
D.
none of these

Solution:

QUESTION: 60

Which one is unipolar transistor

A.
BJT
B.
MOSFET
C.
FET
D.
none of these

Solution:

QUESTION: 61

A polarized electrolytic capacitor can be used

A.
only in sinusoidal circuits
B.
only in dc circuits
C.
in dc and sinusoidal ac circuits
D.
in circuits having any arbitrary wave form of current

Solution:

QUESTION: 62

A moving coil instrument gives full scale deflection with a current of 100 mA when thepotential difference across its terminals is 50 mV. Calculate the shunt resistance to enablethe instrument to read upto 100 A

A.
10 ohm
B.
8 ohm
C.
6 ohm
D.
5.005 × 10^–4ohm

Solution:

QUESTION: 63

Which of the following motors are used in tape recorders

A.
Reluctance motor
B.
Universal motor
C.
Hysteresis motor
D.
None of these

Solution:

QUESTION: 64

Which motor would you select for vacuum cleaner

A.
universal motor
B.
repulsion motor
C.
hysteresis motor
D.
reluctance motor

Solution:

QUESTION: 65

A tank circuit consist of

A.
an inductor and a capacitor connected in series
B.
an inductor and a capacitor connected in parallel
C.
a pure inductance and a pure capacitance in series
D.
a pure inductance and a pure capacitance connected in parallel

Solution:

QUESTION: 66

The commulator in a dc machine acts as

A.
a mechanical inverter
B.
a mechanical rectifier
C.
current controller
D.
either (A) or (B)

Solution:

QUESTION: 67

Ferranti effect on transmission line is a phenomenon which represents

A.
rise in receiving end voltage on lagging load
B.
rise in receiving end voltage on leading load
C.
load impedance equals to surge impedance
D.
rise in receiving end voltage on no load

Solution:

QUESTION: 68

EHV cables are filled with thin oil under pressure

A.
to avoid formation of voids
B.
to prevent entry of moisture
C.
to strengthen the cable conduction
D.
to provide insulation

Solution:

QUESTION: 69

Arcing on transmission lines is prevented by connecting a suitable

A.
circuit breaker
B.
protective relay
C.
inductor in the neutral
D.
capacitor in the neutral

Solution:

QUESTION: 70

In half wave rectifier, if an a.c. supply is 60 Hz, then what is the a.c. ripple at output ?

A.
30 Hz
B.
60 Hz
C.
120 Hz
D.
15 Hz

Solution:

QUESTION: 71

A power supply has full load voltage of 24V. What is the no load voltage for 5% regulation?

A.
12V
B.
23V
C.
25V
D.
6V

Solution:

QUESTION: 72

For an existing ac transmission line, the string efficiency is 80%. If dc voltage is supplied forthe same set up, the string efficiency will be

A.
< 80%
B.
80%
C.
90%
D.
100%

Solution:

QUESTION: 73

When excitation is altered in an alternator connected to an infinite line, it provides acorresponding change in

A.
terminal voltage
B.
speed of rotor
C.
power generated
D.
power factor

Solution:

QUESTION: 74

Lightening surges are arrested by

A.
corona
B.
ferrente effect
C.
skin effect
D.
none of the above

Solution:

QUESTION: 75

The rms value of a half wave rectified currentis 10A. Its value for full wave rectification would be

A.
B.
C.
14.14
D.
20

Solution:

QUESTION: 76

176. For the wave given below, the rms value will be

A.
2A
B.
1.528A
C.
1.1A
D.
1A

Solution:

QUESTION: 77

177.The equation for 25 cycles current sine wave having rms value of 30 amperes will be

A.
42.4 sin 50 pt
B.
42.4 sin 25 pt
C.
30 sin 50 t
D.
30 sin 25 t

Solution:

QUESTION: 78

A 220 V series motor takes a current 35 amp and runs at 500 rpm. Armature resistance =0.25W and series field resistance = 0.3W. If iron and friction losses amount to 600W. Whatis the armature torque

A.
134N
B.
138N
C.
154N
D.
156N

Solution:

QUESTION: 79

Illumination level required for precision work is around

A.
50 lm/m²
B.
100 lm/m²
C.
200 lm/m²
D.
500 lm/m²

Solution:

QUESTION: 80

Lumen/watt is the unit of

A.
light flux
B.
luminous intensity
C.
brightness
D.
luminous efficiency

Solution:

QUESTION: 81

A DC generator used for ac welding should have

A.
rising characteristics
B.
dropping characteristics
C.
straight characteristics
D.
none of these

Solution:

QUESTION: 82

The load taken by welding transformer is

A.
purely resistive
B.
non-inductive
C.
highly inductive
D.
resistive & inductive both

Solution:

QUESTION: 83

In rectifier circuit shown above, what should be minimum peak-inverse voltage (PIV) ratingof the diode

A.
12V
B.
C.
24V
D.

Solution:

QUESTION: 84

In an open circuited p-n junction diode space charge density at the junction is

A.
maximum
B.
zero
C.
positive
D.
negative

Solution:

QUESTION: 85

In an HVDC system

A.
both generation and distribution are d.c.
B.
generation is a.c. and distribution is d.c.
C.
generation is d.c. and distribution is a.c.
D.
both generation and distribution are a.c.

Solution:

QUESTION: 86

In order to have lower cost of power generation

A.
the load factor and diversity factor should be low
B.
the load factor and diversity factor should be high
C.
the load factor should be low but diversity factor should be high
D.
the load factor should be high but diversity factor should be low

Solution:

QUESTION: 87

Mho relay is usually employed for the protection of

A.
short lines only
B.
medium lines only
C.
long lines only
D.
any line

Solution:

QUESTION: 88

The making and breaking currents of 3- f ac circuit breakers in power system arerespectively in what form

A.
rms value, rms value
B.
instantaneous value, rms value
C.
rms value, average value
D.
instantaneous value, instantaneous value

Solution:

QUESTION: 89

For a fault in power system, the term critical clearing time is related to

A.
reactive power limit
B.
transient stability limit
C.
short circuit current limit
D.
steady state stability limit

Solution:

QUESTION: 90

A cable has inductance of 0.22 mH per km and capacitance of 0.22 mF per km. The surgei mpedance of the cable is

A.
28W
B.
33W
C.
42W
D.
50W

Solution:

QUESTION: 91

The shunt winding of a motor has a resistance of 85W at 22ºC. When the motor runs at fullload, its resistance increases to 100 ohms. The resistance temperature coefficient of winding perOºC is 0.004. The rise in temperature of the winding will be nearly

A.
20ºC
B.
50ºC
C.
70ºC
D.
100ºC

Solution:

QUESTION: 92

Temperature coefficient of resistance is expressed in terms of

A.
ohms/ohm ºC
B.
mhos/ohm ºC
C.
mhos / ºC
D.
ohms/ºC

Solution:

QUESTION: 93

For the same peak value of voltage which wave will have the highest rms value ?

A.
since wave
B.
half-wave rectified sine wave
C.
square wave
D.
triangular wave

Solution:

QUESTION: 94

A wire 2.5m long is bent into a square. A current of 100 A flowing through the wire will produce
a magnetising force at the centre of the square, equal to

A.
B.
C.
D.

Solution:

QUESTION: 95

Common base configuration is little used because

A.
it has low input impedance
B.
it has high input impedance
C.
it does not heat up
D.
it has very high gain

Solution:

QUESTION: 96

The decrease in terminal voltage of a shunt generator is due to

A.
armature resistance
B.
armature reactance
C.
armature leakage
D.
none of the above

Solution:

QUESTION: 97

The armature voltage control is considered as suitable, in case the dc machine is driven at

A.
constant torque
B.
constant speed
C.
constant load
D.
constant current

Solution:

QUESTION: 98

Interpoles are usually wound with

A.
very fine gauge copper wire
B.
heavy gauge copper wire
C.
insulation material
D.
interpoles do not need winding

Solution:

QUESTION: 99

If the flux of dc motor approaches zero

A.
its speed will approach zero
B.
its speed will remain unchanged
C.
the motor will stop
D.
the motor will tend to run at infinite speed

Solution:

QUESTION: 100

Which of the following is not a routine test on transformers

A.
polarity test
B.
Radio interference test
C.
core insulation voltage test
D.
impedance test

Solution:

100 Questions MCQ Test Mechanical Engineering SSC JE (Technical) | Mock Test: SSC JE (ME)- 15

For a single phase capacitor start induction motor which of the following is valid ?

To avoid arcing, connect suitable value of in earthing

What is the value of the current I in the circuit shown below ?