ies electrical engineeering 2015

7/23/2019 IES Electrical Engineeering 2015

1/48


2/48

1 The max: mum space rate

of

change

of

the

function

which

is in increasing direction

of

L1e

function is

known

as

a)

curl

of

the

vector function

b) gradient

of the scalar function

c)

d i v ~ r g e n c e

of

the

vector function

d)

Stokes

theorem

2.

The

fielC

strength at

a

point of

finite

distmce

from

an

infinitely long

straigh:

u n ~ f o r m l y charged conductor is

obtc..ined

by considering the radial

component

and

the

longitudinal

component of the

forces

acting

on a

unit

cha:-ge

1t the point, by the charges

or_

the

elenental

length of the

conductor

The

res.1ltant

field

strength

is

a)

the

sum

of

R-components,

wher_

the

sum

of -components is zero

b) the sum

of

-components,

when

the

s un

of R-components

is zero

c) the

sum

of both R- and L-

conponents

d)

a\'erage of the

sums of R- anc

L-c)mpanents

3.

Con3.der

the

following

standard

symbols

for

two-port parameters

:

1. h

12

and

h

21

are

dimensionless.

2. h

11

and B have dimensions of

ohns.

3.

C

is dimensionless.

4. is

dimensionless.

Whi::h

cf

the above are correct?

a) .

1,

2 and 3

only

b)

c)

(d)

1 2 and 4

only

3 and 4

only

1 2, 3

and

4

B-GTD-0-FDA.' 6 A

4

A

conductor

ha.ring a cn:ss-sectional

->

area a sq

m

car=ying

curreon:

I j A

lie3

in

a

magnetic

fidd

-> -> ->

2

B = 3

i j) Wb'm

The

force

density

L

the

C:Jr.ductor

is

a)

Bo

...

b)

Bo

f :

Ik

i

a a

c)

o _

Ik (c .)

o }

a

a

4

-- -}-

where i j and k

c.re crthogonal

uni:

vectors.

5.

For electromechanical

n r ~

conversion.

a

magnetic

field

is e r r . : p l o ~ d as

the

medium

rc..ther

than e ectric

field

because

{a)

the stxed =nergy

density fo:-

practicc.ble Je d strength is low in

the

electric fiek

b)

the

electric

field

pre:;errts

insulatior

problerr.

c)

the

spe:::ific

magnet:c ;oss is more

than

the sp=cifc diele:::t:ic loss

d) None

of the

axve

f..

The

reliability of a::1 instrument refers to

a)

the

measure:m=r.t

of ch3.r.ges due tc

temperc..ture v-=iriaticn

b) the degree tc ..._ hich repeatabilit)

c)

(d)

continu=s

to

specified

lirr.it;;

remain

the life of

a::1 instrumen:

withir:

the extent t.J

'Nhich the

character

istics

remain iir_ear

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3/48

7

f the current

density

inside a

straight

co nductcr is uniform

over

its cross

se:tion, the

flux density variation

inside

t h ~

conductor

at different distances

frc:m

its centre is

(a}

linear

bj square of the distance

(c)

inverse

of

the distance

(d)

exponential

8

The law which states that the

line

~ n t ~ g r l of the magnetic field around a

:::lo 3ed

curve is equal

to

the

free current

:hr:mgh a surface,

is

, a) Gauss

law

1

b)

Tellegen s theorem

. I

tc,

Coulomb s

law

fd) Ampere s law

9 In

an electrodynamometer

wattmeter

(2} the

fixed coils

providing

mag:1etic

flux

are connected across the

power line

(J)

the compensated wattmeter

improves

its accuracy

by

using

windings

with

opposite

currents

with respect

to series

windings

fc)

if

the

full-scale

power

measured

is

100 W,

then

the

half-scale power

will be

10

W

d) I t can measure a.c. power but is

unsuitable for d.c.

power

10 v

:e

(a)

(b)

(c)

d)

1/2

- - - - - - 7 - 1 ~

a}

High

stiffness

and strengths

b)

Low

densities

c)

Unusual

electrical property

d) Non-C.uctile

36 The evidence for the importance of

electron-phonon interaction

in super

conductors

comes from

a}

Meissner

effect

b)

Josephson

effect

c) isotope

effect

d)

flux

quantization experiments

B-GTD-O-FDA/62A

37

.vhich

one of the

following

mate:ilis is

used

fiJr cc.b:.e i::1sulation?

a}

Phen l f i J r m a l d e h y d ~

b)

P c l y t ~ t r a f l u o r o e t h y l e n e

c)

PclyviqrJ cUoride

d)

Acrybnitrile

butaiiene

styrcr-=

38

::< or h i g h s p ~ e j readin5 and

sto:::-:::1g

of

informaticn a

computer, the material

used

is

a)

f r r i t ~

b) p i ~ z o ~ l e c t r i c

c)

pyroelectric

d) f e r r o m : ~ . g n e t i c abcve 76.3 o

39 The

temperature

t o ~ which an

anti-fe:::-rom.:l.gnetic rrateria: bex roes

paramagne:ic is called

a)

peak

t ~ m p e m t u r e

b)

Ni-el tc

rr:perature

c)

cr.

ic

: ~ 1 t ~ m : J e r a t u r e

d} W i s s

te

: 1 p ~ r a t u r e

40 Nhich dfecr. r.he ccnverse of ~ l t i r

e:fect?

a) Seebeck effect

b)

Tl-.orr.soL effect

c) Hall ~ f f e d

d)

Jcule effect

[P.

T.

0.

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8/48

41

Magnetic mate:ials

which

may be r e a d i l ~ ;

magnetized ir: either direction are

(a)

soft magnetic

materials

(b) hard magnetic

materials

c) ::,.igh eddy

current

loss

materials

(d)

high hyseresis loss

materials

42. Consider the

following

statements

regarding

a fe::-romagnetic

material

:

1. Below

tl

e ferromagnetic

Curie

tempera::ure,

the ferromagnetic

materials

exhibit hysteresis

effect.

2. The

coercive

force is the

field

required

tJ reduce the

flux

density

to

zero.

Which of the

3.bove

statements is/are

sorrect?

(a)

Both 1

an_i

2

fb) Neither 1 :1or 2

(c.

1 only

d) 2 only

43.

T:1e

impact

ionization phenomenon

in

semiconductor may be

viewed

as the

reverse

process of

t:z) radiative recombination

(b)

Auger reco:nbination

-::) surface rec:::>mbination

i) S h o c k l e y R ~ a d H a l l

recombination

44

Refractive index of

a slice

glass

can

be

r ~ d u c e d

by

d o p ~ n g

it with

tiny

amount

of

B-GTD-O-FDA/62A

45 An

iron-cored

c ~ o k e coil has an

eqdvalent ::-esh:.tance

of

5 Q. It

draws

10 A

when

-:he a?pLed voltage is 24(

V,

50

Hz.

Its

induc--:an:e and

p o v ~ r factor

respectively are

(a} 75 mH anc.

CJ

(lag)

(b)

747 mH ar:d

0 1 (lag)

c) 747

mH ar:d 0 208 (lag)

(d) 75

mH anci

0208

(lag)

46 A

voltage

of 1

. I

V

is app2ied to

an

impedance of = )4)

Q . What c..re

the

values

of

:Jctive power, reacbve

power and

volt-a:nperes

respectively?

a) 1200

w.

1 2 ~ 0

VAR and

2=00 VA

(b)

1600 W.

16:0

VAR and

2200 V. \

c)

1200 w

16=:0 VAR

and 2000 VA

(d)

1600 W,

12)() \ AR and 2200

VA

47 The

voltage ocroSf.

a: 1. impedan::e

Z

is

100L15

V

ar.d the :::urrent thro-Jgh is

2 L 45 A. :: he 3Ctive and

the

reactive

powers in

::-espectively

are

(a)

1000

W

and

1732

VAR

(b)

500

W and 732

VAR

(c)

1000

W and SOCO VAR

(d)

500

W and 6 JOC VAR

48

An

a.

c.

source of ~ : ) )

V

r.m. s_ supplies

an active

power of

1200

W and 3.

reacbve

power

of 1600

VAR to c. loac

The r.m.s.

current and the powe:- factor

of the load respective

y

are

a) 10 A and

06

fb)

8 A and

)8

(c)

10 A and 08

d) 8 A and 06

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9/48

49

A

shunt

capacitor

used

for reactive power

compensation is operated at 98% nf its

rated frequency

and

95% of its :-ated

voltage. The reactive power supplied by

this capacitor

(as

compared

to

its :-ated

capacity)

is

(a)

79

lower

b)

115% lower

(c)

115% higher

(d)

79

higher

50

Consider two nodes A

and

B

conne

::ted

by an impedance of

j

Q. f

the

voltages

at nodes A and B are

100L30"

V and

lOOLO V

respectively,

the real pcwer

that

can be transferred

from

node A to

B

is

{a)

1120

W

{c)

2769 W

b) 2000 w

(d) 2769 w

51 None of the poles of a linear cor:::rol

system

lies in the

right-half of s-plane.

For a bounded input, the output of this

system

a)

is always

bounded

b) could ::,e unbounded

(c) always

tends to

zero

d)

None of the

above

52

If

the diameter of a copper wire is

increased by two times

keeping

:ts

terminal

voltage same, then the

d:i.ft

Yelocity will

(. .:1.}

becorr.e

twice

b) become half

(c) become

four

times

d)

remain

unchanged

B G T ~ O F D A / 6 2 A

53 Phase lead compem;crion

a)

increal:.es bandwidth

and

increases

steady-

state

err::r

b) de::reases

bandvridL1

and

decreases

s t e a . d ~ 1 s t a t e

e:-ror

(c) will nJt affect ba::1dvridth but

decrea&es steady-

3 t a t ~

error

d)

i n c r e a s ~ s b a n ~ . d t h

but

will not

affect s:eady-sta:: error

54 The

Thevenb

equiva1fnt voltage

and

resistan.::e across B l:;JOwn in the figure

respecti1ely are

r ~ .

A

t

2.Q

fa) 5 V

and

5 Q

(b)

25

V

and

3

Q

( ::)

35

V

anc

2 Q

(d)

25 v

anc

5 Q

55 n.e theorem

which states that

in

any

1L. 1ear,

no:1.-linear, passi-..e,

active,

time

variant

ar_d time-invariant

n: twJrk,

the

s.1mmation of i n s t a n t a : : : e o u ~ pcwers

is

zero will be cElled as

fc.) Tellegen's theorem

b.l com

pen

sa ion the) -: Til

, c} recipncity

theorer:J.

super::>osition thecn-m

[ P. T.

0.

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10/48

56. Trans:isnts are

caused

because

1.

the load is suddenly connected

to

cr disconnected

from

the supply

2. cf

the

sudden

change in applied

voltage

frc:n

one

finite

value

to

the

ether

3. of :he

change in stored energy in

inductors

and

capacitors

W_ 'lich of

the above statements

are

corre-ct?

c.,

1 and 2 only

t; 1 and 3 only

(c) 2

and

3 only

ci; 1, 2 and 3

57. A uni : impulse function is defined as

1. a

pulse of

area 1

2. a pulse compressed

along

:1.:J::izontal axis

and stretched along

vertical

axis

keeping the area unity

3.

u

4.

< ,t

= 0,

t #

0

Whic:1

of the

above

statements

are

corre:t?

a}

2

and 3

only

(b,' 3 and 4

only

c)

2, 3

and 4 only

(d,

1,

2,

3 and 4

B GTD 0

FDA/6 A

O

58.

The derivative

of a

parabolic function

becomes

a) a u n i t i : n p u ~ s e

function

b) a ramp function

(c)

.a

gate

f..mct.on

d) a triang.u.lar functic n

59 Which of the

fcllowing can

produce

maximum

induce-d

voltage?

a) 1 A d.c.

curent

b) 50 A

d.c. current

(c) 1

A, 60 Hz c..c. current

d) 1 A, 490 Hz a.c. current

60 The Laplace tr:m.sf.)rm of the

waveform

of

the

following figure is

v t)

A

0

a)

{b)

(c)

d)

1

1\

I

3

A

1

s -3s -4s

2

e --e e

s

A

1

s -3s -4s

- e e e

s2

A

1

s

-3s -4s

e e e

s2

None

of :he

above

4

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11/48

61 P.r. ideal current source is connect=d

to

the

disconnected circuit shown in

the

figure

at =

0.

The time constant

c f

the

circuit is

source

RC

2

(o)

RC

(c)

2RC

(d) RC

2

62

f the Q-fa:::tor of a coil at resor:ant

frequency of

15 MHz is

150 for a

se:ies

.

resonG.llt circuit,

then

the

correspondng

bandv.idth is

(a}

225

:\1Hz

(b)

1 )6 W.Hz

c, 50

kHz

(dJ 1C kHz:

63

A

one-port network

consists

of a

capacitor

c f 2 F

in

parallel with a

resistor of _ Q Then the input

3

adrdtr:e.nce is

(a) 2s 3

(b)

3s

+

2

c)

2 1

-

3

(d)

~

3

2

B-GTD-O-?DA/62A

64

In a

two-wat:meter

me-thod of

measuring

1=ower

in

a balance: ~ p h a s e circuit, the

n.tio of -:he two v e.t-:metecr readings

1s

1 : 2. The circuit J=Cvorer fe.ctor

is

(a)

0707

(b) 05

c.J

0856

(c)

indeterrr.inate

65 A

b a l a n ~ e c d e l : a ~ o n n = c t e d load

16 + j 12) Qjphase i:s

connected

to a

3-phase 230 V

baie.nced

supply. The

liLe cur:-et1.t and

the

::-eal power

drawn

respectiYely

are

{aJ 9 ~

A and

317 5W

(b)

115

A and

634

kW

c) 199 f.. and

624 kW

, d) 115 . ~ d 317 kW

66 The

servomotor

differs fro:Jm tbe standard

mcnors pincipally

in

t::Iat,

_t

has

(a} entirely differen-:

c:mstruction

(b) high iner.ia anC. tence

Ligh

torque

. ~ ) low i n ~ r t : a and

lm:.;

torque

(d)

low

iner-:ia

and h i g h ~ r starting

torque

67 A

: : > a ~ a n c e d

bad of 5 "4 is connected

in

delta. What is the i m p ~ d a n c e

per

phase

o::

tj_e eqLivalent star c::>nne:::tion?

c.)

5+

)4

(h)

166+

j1


12/48

68.

The vector i s an e;genvabe

of

-2

I

A

=l

2

- 1 2

3]

1

-6

-2

0

)ne of the eigenvalues of A

, a) 1

, b) 2

1

c)

5

, d)

7

69

Ir_

an electric circuit, the nLmber

of

independent

neshes

M

is

ia)

B

N + 1

ib)

N +

1

tc)

B

N 1

d) N

-1

where

B

is number of branches and

N

is

number

of no:ies.

70

Frequency

counter can

be

used

to

measure

1.

fundamertal frequency

of

inpu:

signal

..

.< .

fundamer

tal and harmonic

frequencie-s of

input signal

time

interval between two

pulses

4.

pulse wid

:h

Which of the

above statements are

correct?

a)

1,

2,

3 ar_d 4

oJ

1, 2

and 3 only

c)

2, 3 anc 4 only

d)

1, 3

anc

4 only

B-GTD-O-FDA/62A

12

7._. In vector i m J ~ d a n c e ::neter, the cJVerage

o: the instrument -::an

be

obtained with

c)

V I

chc...racteri8ics

of

the test

syste:o.

t) power-

requency

plot

c.) sweep 1 ::-equency p.ot:s

of

impedccce aLd

phase

angle versus

frequency

C.)

v o l t a g ~ -angle pl)t

72.

In the circuit

;;he-wn below, the ammeter

reads

01 P_ and t te voltme:er

reads

10

V.

The

i::ltem:tl

resistance of the

ammeter

iE

l

Q

and

t:1at

of the

vo_tmeter

is

500

Q.

~ h a t

is

t r_e value of R?

~ - - - - f A \ r - - - - . - - - - - ,

\.:.:..I

I

~

a_t

lOOQ

b) 125 Q

(c,

90Q

d)

120

Q

7:3. The

open-lcop tra:1s:er

functi::m

of

a

feedback co::1trol sys-:em

is

giv=n

by

G(s)H(s) = K(s'+ 8

s

s + 41 :s + 4s + 8

In the :root locus diagram of the system,

t h ~ asympbtes of :he

root

loci

fo:

large

values of 1


13/48

74 A 1

rnA

galvanometer with inte:-nal

resistc.nce

of

50 Q

is

to

be

converted to

measure

:A (full-scale).

What is the

vaLle ::>f t h ~ shunt resistance

required

for

thi-3 conversion?

a} 1

Q

b) 0)1 Q

c)

1k

d) lO

Q

75.

A

50 J l }\ ::>asic

d Arsonval movement with

an ir:temal

resistance

of

500

Q is

to

be

used

as a voltmeter. The value of the

multiplier resistance

required

measure

a

full-scale voltage

range Jf

0-5

volt3 is

a) 9995kr;

b) 995 kQ

c)

9-99

kQ

d)

099kQ

76

The power factor of a circuit in whicl".

voltage

and current waves

are

non

sinusoidal

is defined

as

a)

it is

the

cosine of

the

angle of phase

d i f f e r ~ n c e between

the voltage and

c1..:.rrent

waves

b) it :i s the cosine

of

the angle

of

phase

difference

oetween

the

two complex

waves

c) it is tl.e coEine of the angle of

phase

difference ::>etween two equivalent

sine waves

having

respectively

r.rLs. values equal

to

those of the

voltage

and current in the circuit

d)

it is

the sine of

the

angle of

phase

difference between

the

two complex

waves

E GTD O FDA/62A

1 3

77. The max:inum p::>wer demand of a

consumer

2 kW

and

the corre- .

sponding

iaily er_ergy consumption

is

30 units.. w:1.a:

is

the correspcnding

bad

factor?

a)

025

b) 05

c)

062 :

d)

075

iS.

Time

r-es::>Onse of

an indic :tting

instrument

is

de-::ic.ed by which the

fo]owing ::yste:m?

a) Mechc.nical system provided

by

pivot

and

.'e.:rel

bearing

b)

Contrc lling s:?Stem

c) Deflecting 5ys':em

d) Damphg s_,'stem

7;., What

happens

to

the

resistance { a

conductor if i:s l ' ~ t h is increased three

times and Ciameter IS

halved?

a)

Resista::1ce ::-er:-.a:ns

the

same

b)

Resistance is

~ n c r e a s e d

3

times

c) Resistance

is

increased 6

times

d)

Resistance

i3 increased 12 times

80

An

in::egrator cype D\'YI (digital voltmeter)

contains

a 1

0(1 kQ anci

1

f i F capacitor. I f

the voltage a?pliec. to

the integrat::>r

input

is 1 YoH w:'la::

voltage will

be

present

at the outp:....t of the integrator

after

1 secon:P

a)

v

b) 1 v

c)

10

v

d)

100 v

rP .T.O

www.examrace.co


14/48

81. In measuring resistance by voltmeter

ammete-:- method, the voltmeter

can

be

connectr:xl either across

supply or

across the resistance.

f

the resistance

is

low,

th.:

voltmeter should

be

connect::d

(a) acoss the supply

(b)

acr::>ss

the

resistance

(c)

either across

the

supply or across

:he

resistance

(d)

neither

across the supply no::-

across

the

resistance

82

A

bridge

circuit works at

a

frequency cf

2

kEz.

Which

of

the following can

be

usee

as detectors

for

detection of nuJ

condi:ims in the bridge?

(a)

Vi Jratior_ galvanometers and heaC.

ptones

(b)

Headphones and

t u n ~ l e amplifiers

(c) Vibration

galvanometers

and

trmable amplifiers

(d) Vibration

galvanometers,

head

phones and tunable

amplifiers

83 A dual-beam CRO

(a) ha.s

one

set of vertical deflectio::1

p ~ t e s

(b) h::ts two sets

of horizontal

deflection

p.ates

(c) llils two

separate

electron

beams

(d)

None

of

the

above

B-GTD-0-F[A/62A

14

84. I f the bandvvidth of an oscilloscope is

I 0 MHz, whc.t is the fastest rise time 3.

::quare wave can

have

to be accurately

:-eproduced >y the

instrument?

fa}

10

ns

1

b)

35 ns

. c} 28 ns

fd) 100 ns

85.

l

Wheatstone

brXige

has

g;Jt thre:e

res:stances take::1 l o ~ s e directicn

as

120

Q l O Q

:tnd 150

Q. The value

Jf

the

fourth

resirtance for

n.1L balance

would

be

(a) 150

Q

(c)

300 Q

(a) 120 Q

(d) 750 Q

86. .\

capacitive transducer c o n s i ~ t s

of

tvo

pa::-allel

plctes >f diameter 2 em each

and separa:ed 1:y an air ga? of 025

mm.

What is

the disphcement seLsitivityr

(a) 200pF/cm

(b)

-

300

pF

I em

(c) -444

pF I

em

(d) 44 -4 pF I n

87. An analog t::-anscucer wi:h a

0-10

V

in:mt

is able to

distinguish a charge of

1 1 mV in its input

signa . What is

ths

number of bitl: cf

an

AjD ccnverte:r

i Tl

binary coC.e sc

that

the

digital output

has

almost

the:

~ r n e

res:::>lution

as :he

trmsducer?

(a)

8

d 12

(b) 10

(d) 4

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15/48

88

l h ~

transfer function

C I

of the

syste::1

shown in the figure is

R ~

89 The transfer function of the circuit as

shown in the

figure

is expressed as

---,.----0

~ 0

R-C network

a)

R

1 sRC

iJ)

s

1 sCR

c)

1

1 sRC

d) 1 sCR

B GTD O FDA/62A

15

90 A 3-turn 1(0 kQ poten:iomete::- with 1

linearity

uses 30

V

supply. What

is

the

potentiometer

constant?

a) 01 V/ turn

b)

10 V; turn

c) ~ ;

.;

fturr_

d) 03

V/ :urn

91.

A

quiescent

.inear time-invariant system

subjected

to a unit step inpu1 u t) has

the response c t)

=

te-t t ~ 0. Then

C s)

R s) would be

Linear time-

u tJ

- - - ~ invariant

c t)

sy.;;tem

l

a)

s s

+ 1

c)

d) None of the

above

I

P.

T.

0.

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16/48

92.

Th:: characteristic

equation of

a

closed

bop

syste:n

is

s

2

+

4s

+

16

= 0.

The

natural fre-quency of oscillation

and

d.am?ing ccnstant respectively

are

1

2}

2

rad/

s

and

-

2

1

( YI 2.f3 rad/

s

and .f3

d

1

+ rae.

.s

an -

2

1

fdl 4

rad/s

and

..J2

93. Ccnsider

the

following

input and

system

-:?:;>es

nput type

System

type

Unit stei=

Type

0

Unit

ramp

Type 1

1

Unit parc.bolic

Type

2

1>\ hich

of

tl:.e following

statements are

co::-rect?

~ .

Unit

step input

is acceptable to all

the three types of

system.

Type 0 system

cannot

accept unit

parab-::>Lc input.

Unit

ramp input

is acceptable :o

Type

2

system only.

A) 1 and only

1 and 3 only

c;

2

and

3

only

dJ 1, 2 and 3

B G T D ~ F D A / 6 2 A

16

94 -

A sensor requires 3(

1

s to indicate 91)

of the respor_se tc a step input.

t f

the

sensor is a f l r s t o r d ~ r system, the ti:ne

constant

is

[given, loge 01) =

-2

3]

fa) 15

s

b)

13

s

{c) 21 s

-:1)

28

s

95 .\ unity feedbc..ck s:rs.tem has open-loJp

transfer function

G s)

= K s +4)

s

+ l

.s

+ 2)

The portims of the real axis that lre on

b e root k>ci are

between

(a)

s = -

2 an.d

s = - 4; s = -

1

and

+

=

(b) s

= 1

an:i s

= -

2; s

= 4 and

e x

(c) s =

0

and s = -

2 .

beyond s = -

4

d) s = 0

and

s

= -

1

96. J: is the

fun:lamental voltage,

v3 and

\ ~ i

are the amplituces of the 3rd an::l 5-:h

harmonic and

then

the

tJtal

harm)dc

distortion

cf

tr.e

system will be

b}

y

X

fc X y

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17/48

97. The

characteristic equa tion

of

a feed:mck

sy "tem

is

s

3

s

Ss 10 =

0. F::>r a

stable

sysem, the

value

of

K shouli be

~ e s s than

ta 1

( J) 2

C) 45

98 Ccnsider the following

statements w i t ~

re3ped to Routh-Hurwitz criterion

:

1 :-:can

be

used to determine

relati,;e

stability.

2. It

is

valid

only

for

real

coefficients

o: the

characteristic

equation.

3. t

is applicable only for

non-linear

S}stems.

4.

It does not

provide

the exact

location )f

closed-loop

poles in

left- or right-half of s-plane.

Which of the

above

statements

are

c o r r e c t ~

a)

1, 2

and

3

only

b) 3

a:1d

4

>Lly

c)

1, 2

and

4

only

d)

1,

2.

3 and 4

B-GTD-O-FDA J62A

17

99 The first : le:nent of each

of

the

ro' I\.'S

of

a

Routh-Hur.vitz

stabili.;-:y test

sho\\.ed

the

signs as follows

:

I

l

IV

v

Consider

the foiowing s t t e m e n t ~

The

s y ~ t e r r has three roots

in

the

right-hdf of s-plc.ne.

2.

The system has

three roots in the

left-half of

s-plan=

3. The ~ y s t e m is statle.

4.

The system

is

un,>-:able.

Which of the above statements a)out

the system are currect?

(a)

1 and 3

(b)

1

and

4

c)

2

and 3

d)

2

and 4

100

Consider thE

fcllowing

statements alnut

rcot

locus

:

1.

The roct locus syr:unetrical

about

real ax:s.

2. f

a roo-: lccus

~ r a n c h moves along

the real axis fnm an open-loop pole

to zero or to

in:::1ity,

this root loc

J.s

branch

is

::alled

real root branch.

3. The

bre3.ka'lh'a:'

pcir:t3 of

the

rOJt

locus

ar: the

soluticr_s

of

d = 0.

s

Which of tl-_e

abC\:e statements

are

correct?

a) 1

and

2

o n ~ y

b)

and 3

on:y

c)

2

and

3

)n}y

d)

1, 2

and

3

[ P.

T. 0.

www.examrace.co


18/48

-

101

The low-frequency circuit impedance

and

the

high-frequency

circuit

impedance

for a series resonant

circuit

r e s p e c t i v e ~ ;

are

a) capacitive

and inductive

b) inductive

and

capacitive

c) resistive and inductive

d) capacitive a.. 1d resistive

1 02

The

state-variable

formulation of a

system is

x

=Ax + Bu

y

= 1 0] x

where

1be system transformation

would

be

s+2

s

2

+ 5 s 6

2s+ 5

b)

.s

2

+

5s + 6

( C)

2s

5

B-GTD-O-FDf./62A

18

103

Foc the folloiNing

network

work as

lag

compensatcr

~ value

d R

2

s.l.ould

be

= 20

a)

I

2

20

:2

fb) R

2

::;

10

Q

R

2

c

k2C::; _ 1 _

2

d.) Any value

of

R

2

104 h ~

z-transform X z) of

si?;Pal

x

[

n] = T

1

u n)

w h ~ r e u :1) is seque :1ce

cf

unit pulses

is

a)

{b)

c)

d)

J,

z 1

z

z-1

z

z a

1

z a

105 How many ro:>ts of the ~ o f i o \ . J i n g equ3.tion

lie in L1e

right-half

Jf s-p. ar.C'?

2s

4

S

3

+2s

2

T 5 ~ + 1) = 0

a)

1

b) 2

c) 3

d) 4

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19/48

Directions

Each of the next

fifteen 15) items

:onsists d

t-vo

ste:tements,

one labelled

as

'Statement II) and the

other as

'Statement (II)'.

examine L l . e ~ e

two statements carefully

ar_d

~ e l e c t the answers

to

these

items

using the

:odes

given

below

:

Co ies

:

a)

BcJth Statement (I) and Statement

(II)

are

individually true and

S1ateme:1.t (II)

is the

corre::t

eJ.:planation of Statement (I)

b) B ~ J t h Statement (I) and Statement

UJ) are individually true but

Statement (II) is

not

the

corre::t

e:l-:planation of Statement (I)

c) Stateme:1.t

(I)

is

true but

Statement

11) is

fal se

d) Stateme:1.t

(I)

is false but Statement

III) is

true

106 Stah:ment (II

Cdd-workir:g of

a

conductor

material

resul:s in

a decrease in

the electrical

cc::1d1ctivit) of

the

metal because

the

localized strains interfere

with the

el:ctron movement.

Statement (II)

:

S 1 ~ b s e q u e n t

annealing

of

the

ccnd1ctor material

restores the

el:ctrical ccnductivity by establishing

great=r

regularity

in

the

crystal lattice.

107 Statement

(I)

:

A

la:-ge number of

metals

become

's.lpercondLcting'

below a temperatu::-e

w:1icb is ch&racteristic

of

the particular

meta .

Statement (II)

:

S 1 ~ p e r c o n d u c t i n g compounds

and

aloys shJuld necessarily

ha'le

comronent ;

which are themselves

supe:-cond

ucting.

B-GTD-O-::< ::::>A../62A

19

108

Statement

(:) :

In an R L C series c irc.L.it, ex::::ited

from

a

variable

f:-eqLency voltage source,

the circuit bel:aves like a 're ;istive' one

a: a parti.:::ula:- f::-eque:->ey.

Statement

Pl

The

frequency

at which an R L C series

c:rcuit becomes r e ~ i s t . v e in :::haracter,

a part of tbe inpLt e:1.ergy oscillates

between tl:e

inductive and the

capacitive

k m n t ~ of tr_e

circuit.

109

Statement

(:)

:

If a ramp in:rut appHed to a

second-order 3yste:n, the

s8ady-state

e:-ror of

Ll.e

respor. se can be reduced

by reducmg

dampng

and

increasing

natural

frequency

of

oscillation.

Statement Pl

In

the

fre:r1e:1cy : : - ~ s p o n s e

of

a

second-onier

syste:n,

the change

in

s ~ o p e at cne

cf

1he

corner

frequencies

is of

40 dB/ :ie:::ace.

110 Sta-:ement

=l :

The ammeter

lo:tding

~ f f e c t is due to

the high : e s ~ s t a n c e of the ammeter.

Statement Pl

I n c r e a s i n ~

the-

~ s i 3 t a r . c e

of

voltmeter

\\ill reduc:

tht: voltmeter loacing effect.

111

Sta-:ement =l :

In instru:o.er.t:;

-whe-re

sp:ing

control

is

used for

prcviding

co


20/48

112 Sta:ement I) :

Ar:J.:neter and

voltmeter method i;;

u:;ed for measurement of low as well a3

m ~ d i u m resistances.

Sta-:ement Ir1 :

U..rey-Foster slide wire

bridge is

a

modification

of the Wheatstone bridge.

113

S:atenent

I) :

In :he

Kelvin double-bridge

method.

p:-Jvision has been made

to eliminate

the errors

due to

contact

and leac.

resi3ta lces.

S':atc:nent

II)

:

The Schering bridge

is used for

measuring small capacitance

at low

voltages witr_ very

high

precision.

114 S1at:rment I) :

A

~ t r a i n gauge' is an example of

a

T::1:1sducer or an electromechanica:

tr UJ:Sformer.

Stat=ment

II) :

In

t.:1e

'strain gauge', displacement

is

used

to

vary

the resistance of

a

circuit

conponent and the

'strain'

is

m=:a.sured

in terms of

the

change in

the

resistance.

115 S1:3.te:r_em

I)

:

Tre

principle

of the resistance strain

gauge

is

that if

gauge

factor is known,

th= measurement

of

d allows

the

f

d

me3.;;urement

o stra1n

= c .

Statement

II) :

flx- ::mtput of an LVDT is of the order

Jf millivolt.

B-GTD-0-FLA/62A

20

116 Statement II 1 :

Inverse

ro

Jt locus

is : 1 : imc..ge of ~ h e

direct root

~ o c u s

t a t ~ m e n t q :

Root locus is symmetr ::3 1 c..bout -_he

imaginary axis

117

Statement

I)

Centroid i:; the ::>oint vif-_ere

:he

root

loci break frorr_

the rea] axis

Statement II) :

Centroid is tr.e r:oint :n the real

a:-.;:is

where all the c..symptc1es

ink-sect.

118 Statement I) :

At breaka-.vay poir_t

the

S J ~ t e m is

critically d3.mped.

Statement

(Ill :

At the point w:1ere n : t Joci i::1tersr::ct

wi:h the imagir_ary aY.ii:, t:1e ~ y s t e m is

marginally statle

119 Statement I)

:

A

root locus :s

o b t a ~ : : : : d usmg t:1e

clcsed-loop poles.

Statement

rr: :

A

root locus

1s r:lo1ted

using be

open-loop p o l e ~

120 Statement I) :

Inductor i:3 not u 3ed tJ re:ilize a

lag networl:.

Statement

II) :

Incuctor r:rociLces

ti:n.-:

de_ay and

hysteresis

Joss.

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21/48

SP CE FOR ROUGH WORK

B GTD 0 : fDA/62A

2

[ P

T

C

www.examrace.co


22/48

SPACE FOR ROU H WORK

B-G ID-O-FDA/62A

22

www.examrace.co


23/48

SP CE

OR

ROUGH WORK

B GTD 0 FDA/621\

3

[ P T 0.

www.examrace.co


24/48

SPACE

OR ROUGH WORK

B-GTD-0-FDA/624

4

5BS-5:J

www.examrace.co


25/48


26/48

1. A 2000 200 V, 50 Hz single-phase trans

former has

an

exciting current

of

05 A

and a core-loss of 600 W. When H.V.

side is energized

by

the rated voltage

and frequency, the magnetizing current is

(a) 01 A

(b) 02 A

(c) 03 A

(d) 0-4 A

2. A 250 kVA, 11000 V I 400 V md 50

Hz

single-phase transformer has 80 turns

on

the secondary, what is the :naximum

value of flux

?

(a) 2475 mWb

(b)

02mWb

(c) 225 mWb

(d) 552 mWb

3. In a normal

operation

of 400

V,

50 Hz

transformer, the total iron loss is 2500

W.

When the supply voltage and :iequency

are reduced to 200 V and 25 Ez respec

tively, the corresponding loss is 850 W.

The

eddy-current loss at normal voltage

and frequency is

(a) 400

W

(b) 800 w

(c) 1600 W

(d) 200

w

B GTD 0 FDB

- A

2

4. A magnetic circuit has 150 l.lrns-co:l, the

cross-sectional area 5 x10--4 m

2

c:na the

length

of

the magnetic circut 25x m.

What are the values of nugnetic field

intensity and relative p e r m c b i l i t ~ when

the current 2 A and 1otal =lux is

o 3x

3

Wb?

(a) 1200

Tim

and 3979

(b) 300 Tim

and 500>


27/48

7. A 3-phase transformer has 420 and

36 turns on the primary anc secondary

windings respectively. The supply voltage

is 3300

V.

The secondary line voltage on

no-load when the windings are connected

in star-delta is nearly

(a) 22260 V

(b)

1908

v

(c)

164

V

d)

490 v

8. A 4

kVA

transformer has

ion loss

of

200 W and full load copper loss of

200

W.

The maximum efficiency at unity

power factor will be

(a) 909

(b) 856

(c) 806

d)

709

9. A uniformly distributed winding on the

stator has three full-pitched coils, each

coil having

N

turns and e:tch tum

carrying a current

I

The

mmf

produced

y

this winding is

(a) sinusoidal m waveform with an

amplitude 3 N

(b) sinusoidal m waveform with an

N

c.mplitude

3

2

(c) t::apezoidal in waveform with an

amplitude 3

N

-d)

trapezoidal in waveform with an

N

a::nplitude 3

2

3

10

In de machines, the field-flux axis an:l

armature-mmf axis

~

respectively alon.s

(a) direct

aJ


28/48

13

The drawbacks

of

'Am1ature Resistance

Control' method

of

speed control

of

a de

motor are

1. A large amount of

power

is lost in

the external resistance

R

2

This method gives the speed below

normal values.

3. For

a specified value

of

R

speed

reduction is not constant.

t

varies

with motor load.

Which of the above statements are

correct?

(a)

1

2 and 3

(b)

1

and 2 only

(c)

l

and 3 only

(d) 2 and 3 only

14 A

de

motor

running at 2000 rpm has a

hysteresis loss

of

500 W and eddy

current loss

of

200 W.

The

flux is

maintained constant but the speed is

reduced to 1000 rpm.

At

the reduced

speed the tota2 iron-loss would

be

a) 500 W

(b) 400 w

(c) 300

W

(d)

200

w

15 The

speed control

of

de shunt

motor

in

both directions can

be

obtained by

(a) Armature resistance control method

(b) Ward Leo::1ard method

(c) Field diverter method

(d) Annature voltage control method

B GTD FDB

A

4

16. A

10

hp, 240 V de sh 1nt motor, having

armature-circmt resistance

of

05

Q

and

a full-load cunent

of 4 )

A, is started

by

a star.er, such that sections

of

required

resistances in ,;cries with the amlature

circuit should limit

t h ~

starting current

to 150

of

the

full bad

current. The

steady-state emf developed by the

machine at full-load when the arm

of

the

starter is moved to the next step is

(a) 120 V

b)

100

v

(c) 80 V

(d) 60

v

17. A

synchronous

motor

)perates at rated

voltage and frequency and has a load

torque angle

of

30.

If

'Joth

the

terminal

voltage and frequency are reduced by

10 , hen

(a) the load torque z.ngle remains the

same

(b)

the load to:-que angle in:.:reases

(c) the load torque angle decreases

(d) nothing cc.n

be

said about the

torque angk

18

The

n ~ u r e

of a::mature mmf for a zero

power factor lagging

l::md

in a 3-phase

alternator is

a) magnetizing

(b)

de-magnetizing

(c) neutral

(d) cross-magnetizing

www.examrace.co


29/48

19.

The flux/pole in a synchronous motor

with stator not connected to supply is

c

1

and when connected to supply it is

P

1

The no-load current drawn from

the supply under this condition would be

a) lagging the supply voltage

b) leading the supply voltage

. c) in phase with the supply voltage

d) zero

10. A

cylindrical-rotor generator with internal

voltage 20 pu and = 10

pu

is

connected by a line of reactance 05 pu

to

a round-rotor synchronous motor of

synchronous reactance 12 pu and

excitation voltage 135 pu. When 05 pu

power is supplied by the generator, the

electrical angular difference between the

rotors would be

b) 30

c) 60

d)

120

21. The synchronizing power for one

mechanical degree of displacement for

a

3-phase, 20000 kVA, 6600

V,

50 Hz,

12-pole machine having =

165

Q and

negligible resistance is

a) 10246 kW

b)

92 9kW

5

c) 7826 kW

d) 11826 kW

22. For obtaining v ~ y quick bn


30/48

24

A small 3-phase induction motor has a

short-circuit

cmrent

5 times

of

full-load

current and full-load slip 5 .

If

starting

resistance

starte

is used to reduce the

imp:-essed voltage to 60

of

normal

voltage, the starting torque obtained in

terms

of

full load torque would be

(a) 30

(b) L5

(c) 55

(d)

80

25.

The frequency o:: rotor

emf of

an 8-pole

induction

motor

is

2

Hz.

lf the

supply

frequency is 50 Hz, then the motor

speed is

(a)

15GO

rpm

(b)

750 rpm

(c) 375 rpm

(d) 720 rpm

26 For

a given applied voltage and current,

the speed of a universal motor will

be

(a) higher in de excitation than in ac

excitation

(b) h:gher in ac excitation than m de

excitation

(c) same in both de and ac excitations

(d) dangerously high in de excitation

B GTD 0 FDB A

6

27. Two single-phase transfonners A and B

with eqc al turn's ratio have reactan::es

of

j3 Q :md j Q refe:-red to secondary.

When. operated n parallel, the load

sharing cf 100

kW

at 08

pf

1c.g betwetn

A and 3 transfom1ers would respec

tively be

(a) 75

kW

and

5 ~

(b) 60

kW

and 40

kW

(c) 20

kW

and 80 kW

(d)

5 kW

and

-: 5 kW

28. Compared to turbines in the conve:1tion2l

coal-fired thermal 3tations, nuclear

powu

plant turbines use steam at

(a) higher pressure and higher tem

perature

(b) lower pressme and lower

tenpera-

ture

(c) higher pressu:-e ani lower

ten

pera

ture

(d)

lower presstre and higher tem

perature

29

In an L-section filter, a bleeder -esist

ance connected across the load

(a)

p r o v ~ e s

good regulation for all

values

of

loac

b)

ensures lower

PIV of

the dicdes

(c) ensures lower values

of

capaci

tance in the f Iter

(d) reduces ripple content

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31/48

30. The

power

output from a

h y d r o ~ e l e c t r i c

r:ower plant depends

on

(a) head, type

of

dam and discharge

b)

head, discharge and efficiency

of

the system

(c) type of draft tube, type of turbine

and efficiency

of

the system

(d)

type

of

dam, discharge and type of

catchment area

31. Incremental fuel costs

of

two units

and

B of

a power station are

dF

=

oA

~

+400

~

d n

=

0-48

Ps

+ 320

dPs

For the minimum cost

of

generation

of

a

total load

of

900 MW, the generation

zJlocation for and

B

units respectively

are

(a)

200

MW

and 700

MW

(b) 300 MW and 600 MW

c)

400

MW

and 500

MW

c) 500

MW

and 400

MW

32. A

power station

has

a maximu:n demand

of

2500

kW

and number

of

kWh

generated per year is

45x 10

5

. The load

h1.:tor

is

7

(al 1025

(c)

41

(d)

82

3. A long

o v e r h ~ a d

los ;les:; power trans

mission line is terninatt:d with its

characteristi.;

impedJrce.

\Vhile the line

is in operation

(a).

a

resonance cf reactive powers

occurs :n the li:: t:

(b) the line become; ::m:rely inductive

(c) the line become3 :)U:rely capacitive

(d) there IS no retl.:cted

w--ave

on the

line

34. For

~ x a c t

conpensation cf

voltage drop

in the feeder, the boo:;:er

m;.;st

(a) be earthe-d

(b) work on line voltage

(c)

Nork

on its linea p01ii:m

of

V-I

characteri3tics

(d) work on its non-l inear portion

of

1-

I

c h a r a c t e r i s t i c ~

A -

3 GTD 0 FDB

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35 A 100 MVA, 50 Hz turbo-generator

operates at no load at 3000 rpm. A load

of

25 MW is suddenly applied to the

machine and the steam valve to the

turbine commences to open after

06 seconds due to the governor time

lag. Assuming the inertia constant

=

50

kW-s per kVA

of

the generator

rati:1g, the frequency to which the

generated voltage drops before the

steam-flow comroences to meet the

new

load is

(a) 490 Hz

(b) 5015

Hz

(c) 4924 Hz

(d) 4982 Hz

36. In case of single line to ground fault

(a) all sequence networks are con

nected in parallel

(b)

all sequence networks are con

nected in series

(c) positive and negative sequence net

works are connected in parallel

(d) zero and negative sequence net

works are connected in series

(a)

i n ~ a r

modu_ation

(b) Over. modul


33/48

41 When a PNP transistor is properly

biased, the holes from the emitter

(a) diffuse through

the base into the

collector region

b)

recombine with the electrons

in

the

base region

(c)

recombine with the electrons in the

emitter region

d)

diffuse through

the emitter to

collector

42

n

a

P N

junction diode under reverse

bias, the magnitude

of

electric field is

maximum at

a) the edge of the depletion region on

the P side

b) the edge of the depletion region on

the side

(c) the centre

of

the depletion region

on theN side

d)

the

P N

junction

43. A silicon diode is preferred to a

germanium diode because of its

(a) higher reverse current

b)

lower reverse current and higher

reverse break down voltage

c) higher reverse cunent and lower

reverse break down voltage

d)

None

of

the above

44

Compared

to an

ordinary semiconductor

diode, a Schottky diode has

(a) higher re\erse saturation current

and zero

c1t-in

vottage

b)

higher reverse s -.turation current

and higher cut-in

Yoltage

(c) higher reterse saturation current

and lower cut-in voltage

d)

lower revuse satu::-ation current and

lower cut-in voltage

45

Which

of

the followbg

IS

called hot

carrier diode

(a) PIN diode

b) LED

(c) Photo dicde

d)

Schottky diode

46. In a voltage-series-feedback amplifiet

with open lo p gain v and the feed

back factor

{3

the input resistance

becomes

B GTD 0 FDB

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34/48

4

7. Ripple-rejection ratio

of

voltage regulator

is the ratio of

a)

output voltage

to input

ripple

voltage

b)

output power

to input

power of

regulator

c)

input power

to output power of

regulator

d) input ripple voltage to output ripple

voltage

48

Variation in

f

in a

BJT

can cause a

fixed bias circuit to go

a) into active mode of operation from

saturation mode

( J)

out of active mode

c) out of saturation

(d) into cutoff mode from active mode

of operation

49 In a McMurray inverter, diodes are

connected in inverse parallel to thyristors

to

1.

Protect the thyristor

2.

Make the

tum off

of the thyristor

successful

3. Make the tum on of the thyristor

successful

4. Provide path to the reactive

Which

of

tbe above statements are

correct?

a) 1 and 3

b) 1 and 4

c) 2 and 4

(d) 2 and 3

50. Following pulse is applied to an SR flip

flop.

If M is propagation delay, which

of

the

following relat:ons should hold to avoid

the race condition ?

a)

t

< L t

ies electrical engineeering 2015

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