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Q. No. 1 - 20 Carry One Mark Each

1. The pressure coil of a dynamometer type wattmeter is

(A) high I y inductive (B) highly resistive

(C) purely resistive

2.

(A)

3. The following circuit has a source volta through the circuit is also shown.

15.----.-.~ ~~-r---.

1of-----+~

•----t>\---b

(C) •--+<J---b

(D) pu rei y inductive

b

1. 5

1

5

5

1

-1. 5

(D)

R 10k

/

100 200 300 400 Time (ms)

·------j f-----b

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4. The two inputs of a CRO are fed with two stationary periodic signals. In the X-V mode, the screen shows a figure which changes from ellipse to ci rei e and back to ellipse with its m ajar axis changing orientation slowly and repeatedly. The following inference can be made fi'om this.

5.

6.

7.

(A) The signals are not sinusoidal

(B) The am pi i tudes of the signals are very close but not equal

(C) The signals are sinusoidal with their fi'equencies very close but not ~qua

(D) There is a constant but small phase difference between the signals

The increasing order of speed of data access for the following devio

(i) each e Mem ory

(ii) CD ROM r ~ (iii) Dynamic RAM ~ (i v) Processor Registers + ( v) Magnetic Tape

(A) (v), (ii), (iii), (iv), (i) , (i), (iv)

(C) (ii), (i), (iii), (iv ), ( v)

(A) 1 V (D) 1000V

lkfi c lkn

B 2kn

lkfi

A (B) 1m A (C) 2m A (D) 6mA

0 ut of the foil owmg pi ant categon es (1) Nuclear (11) Run-of-nver (iii) Pump Star age (i v )Diesel

The base I oad power pi ants are

(A) (i) and (ii) (B) (ii) and (iii) (C) (i), (ii) and (iv) (D)(i), (iii) & (iv)

9. For a fixed value of complex power flow in a transmission line having a sending end val tage V, the real power I ass wi II be proporti anal to

(A) V (B) V2 (C) 1/V2 (D) 1/V

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10. How many 20 ow /220 v i ncan descent I amps connected in series would consume the same total power as a single 100W/220V incandescent lamp?

11.

12.

13.

14.

(A) not possible (B) 4 (C) 3 (D)2

A Linear Time Invariant system with an impulse response h(t) produces output y(t) when input x(t) is applied. When the input x (t-~) is applied to a system

with impulse response h(t-~), the output will be

(A) y (t) (B) y(2(t-~)) (C) y(t-~)

The nature of feed back in the op amp circuit shown is

(A) Current - Current feed back

(O)Y('~ .------1'=.0

(B) Voltage - Voltage feedback

(C) Current- Voltage feedback

1-- = t= -- 1--

(C) Both are stable

(D) Both are un stab I e

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16. An S CR is considered to be a semi-controlled device because

(A) it can be turned OFF but not 0 N with a gate pulse

(B) it conducts on I y during one half-cycle of an alternating current wave

(C) it can be turned ON but not OFF with a gate pulse

(D) it can be turned ON on I y during one hal f-cyd e of an alternating voltage wave

17. The polar pi ot of an open I oop stable system system is

(A) AI ways stable

(B) Marginally stable

(C) Unstable with one pole on the RH s-plane

lB.

(A) two roots at s = ±j and o

(B) two roots at s = ±j 2 ~ ot in left half s-plane

(D) two roots at s · e root in left half s-plane (0) ~o '"" " ' ::\Yro" io '''"' h•lf '~'~'

19. The asym ptot1 p xim ation of the log-magnitude vs frequency plot of a

-40dB/dec

0.1 2 5

(A) 10(s+5)

(B) 1000 (s + 5)

s(s +2)(s +25)

2.5 ~rad/s

100(s+5) (c) -,-----:7..,.--"='=

s(s+2) (s+25) (D) ....,-B_O_,(s __ +-'5)'-­

~(s+2)(s+25)

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20. The trace and determinant of a 2 x2 matrix are known to be -2 and -35 respectively. Its eigenvalues are

21.

22.

(A) -30 and -5 (B) -37 and -1 (C) -7 and 5

Q. No. 21 - 56 Carry Two Marks Each

(B) 2011: mA leading by go0

(C) 10m A leading by go0

(D) 101tmA lagging by go0

In the figure shown, all elements closed and 52 open. At t= 0, 5 1 i across the capacitor C2 at combination at t=o• will be

~ L_ ______ 4~L_~ _______ 4_J 2F

(D) 17 .5 and -2

t<O, 5 1 remained

,,,~. '''" (0) "" '''"

2 3. • former and em 1 tter foil ower can both be used for 1m ped ance m atchm g at

n d output power Pout 1n both the cases 1 s

(A) P;n = Pout for both transformer and emitter follower

(B) P;n > Pout for both transformer and emitter follower

(C) P;n < Pout for transformer and P;n = Pout for emitter follower

(D) P;n = Pout for transformer and P;n < Pout for emitter foil ower

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24. The equivalent capacitance of the input loop of the circuit shown is

1kfi 1kfi

25. In an 80 85 m 1croprocessor, the con tents of the Accum u latorae: n"e foil ow1n g XRAA ~

mstruct1ons are executed will become MVIB FOH 0 SUB B +

(A) 01 H (B) OF H (C) CJ (D) 10 H

For the V-bus matnx of a 4-bus system g1~r umt, the buses having shunt

-5 2 2.5 o "'V . 2 -10 2.5

elements are Ysus = J 2.5 2.5 -

26.

0 4

(A) 3 and 4 (C) 1 and 2 (D) 1,2 and 4

27.

0 1 2 3 4 times(s)

(B) 2 (C) 4 (D) 6

2 8. The open I oop transfer function of a unity feedback system is given by

G (s) = (e-o.ts);s. The gain margin of this system is

(A) 11.95dB (B) 17.67dB (C) 21.33dB (D 23.9dB

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29. Match the items in List-! with the items in List-11 and select the correct answer using the codes given bel ow the lists.

30.

31.

List I List II

To

a. improve power factor

b. c. d. (A)

reduce the current ripples

increase the power flow in I in e

reduce the Ferranti effect

(C) a--+ 4 b--+ 3 c--+ 1 d--+ 2

Use

1. shunt reactor

2.

3.

shunt capac1 tor

sen es capacitor

4. series reactor

(B) a --+ 2 b --+ 4

(D) a --+ 4 b --+ 1

Match the items in List-! with the items in List-11 and selecto rrect answer using the codes given bel ow the lists.

Listl List~• + Type of transmission line Typa~e relay preferred a. Short Line 1. m lay

b. Medium Line ~f)o Renlacey Relay c. Long Line

(A) a--+2 b--+1 C--+3 --+3 b--+2 C--+1

(C) a--+1 b--+2 C--+3 (D) a--+1 b--+3 C--+2

M Efficiency(%) Regulation (p.u.)

on 100 MVA base

Generator-1 0 20 0.02 G enerator-2 30 0.04

Generate~ 100 40 0.03

of +creased load power demand, which of the following will happen?

( A~ll era tors wi II share equal power

(B G tor-3 will share more power com pared to Generator-1

~ ~.fln erator-1 wi II share more power com pared to G en erator-2

~ Generator-2 will share more power compared to Generator-3

A SOOMW, 21kV, SOH z, 3-phase, 2-pole synchronous generator having a rated p. f= 0.9, has a moment of inertia of 27.5 x 103 kg-m 2. The inertia constant (H) will be

(A) 2.44s (B) 2.71s (C) 4.88s (D) 5.42s

33. f(x, y) is a continuous function defined over (x, y) e [0, 1Jx[O, 1]. Given the two

constraints, x>y2 and y> x2, the volume under f(x, y) is

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34.

35.

36.

Y=l •=-fi y:l H=l

(A) I I f(x, y) dxdy (B) I I f(x,y)dxdy y:O H=Y.: Y=Hl H=y"'

y:l H=l

(C) I I f(x, y) dxdy (D) •=t"=t f(x, y) dxdy y:0H=0 y:O H=O

Assume for si m pi i city that N people, all born in April (a m onth of 3 0 ~· ar collected in a room. Consider the event of at least two people in the r · g born on the same date of the m onth, even if in different years,~ 0 d 1985. What is the smallest N so that the probability of this event e ee ?

(A) 20 (B) 7 (C) 15 f'i~

A cascade of 3 Lin ear Time Invariant systems is causal and ~e. From this, we conclude that

Each system in the cascade is i nd ivi dually causal +

table (A)

(B)

(C)

(D)

At I east one system is uns tab I e and at least n e s•;ti!MI"i s causal

a_2 = 2- j 1; a_1 = 0.5 + j o~· - · ; a1 = 0.5- j 0.2; a2 = 2 + j 1; and

ak = 0; for lkl > 2. Which t wing is true?

(A) x(t) has finite~ ey b se only finitely many coefficients are non-zero

(B) x(t) has ze~ver lue because it is periodic

(C) The im agi r ( t f x(t) is constant

(D) The real pa ~t) is even

+ 37. Th z- rm of a signal x[n] is given by 4z-3 +3z-1 + 2- 6z2 +2z3 . It is

hich of the following is true?

y( n) is non causal with finite support

(B) y(n) is causal with infinite support

(C) y(n) = 0; In 1>3

(D) Re[v (z)],=•'' = -Re[v(z)],=·-··; Im [v(z)],=•• = Im [v(z)],=·-··; -1t s e < 1t

3 8. A cubic pol yn om i al with real coeffi dents

(A) can p ossi bl y have no ex trem a and no zero crossings

(B) may have up to three extrema and up to 2 zero crossings

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(C) cannot have more than two extrema and more than three zero crossings

(D) wi II always have an equal number of extrem a and zero crossings

3 9. Let x2 -117 = 0. The iterative steps for the sol uti on using Newton -Raph son's method is given by

(A) 1 ( 117) xk+l =- xk +---2 xk

(B) 117

xk•l = xk -x;:-

(C) xk xk•t=xk-117 (D) 1 ( 117 Xk+l = Xk -2 Xk + ---

40. F(x,y)= (x 2 + xy)a. +(y2 +xy)a •. It's line integral over

(x,y)= (0,2) to (x,y) = (2,0) evaluates to (A) -B (B) 4

41. An ideal figures. The

3

2

1

v 0~~~------------~~--~.~~~~~--~~-.t-" -1

-2

-3

(A) (B)

t-+

(D) 6 6 -

tv tv

0 t.

0 t, t. t-+

-3 t-- - -3

zkfi

lkn

-

t, t. t. t-+

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42.

43.

A 220V, 50Hz, single-phase induction motor has the following connection diagram and winding orientations shown. MM' is the axis of the main stator winding (M1M2) and AA' is that of the auxiliary winding (A1A2). Directions of the winding axes indicate direction of flux when currents in the windings are in the directions shown. Parameters of each winding are indicated. When .........§/ At switch S is closed, the motor

(A) rotates clockwise

(B) rotates anti clock wise

(C) does not rotate

(D) rotates mom entari I y and comes to a halt

(A)

(C)

+ v:s = 10sin1001tt tv

20 30 time(ms)

10 20 3 0 time(ms)

220V

50Hz

L = (0.1/,.)H

40 50

50

50

Mt r.., = O.ln L~ = 0.1/?IH

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(D) l.sr-----------------,

44. The Current Source Inverter shown in figure, is operated by alternately on thyristor pairs (T t. T 2) and (T 3. T 4). If the load is purely resi theoretical maximum output frequency obtain able wi II be

T1

Dl

04

T4

(A) 125kHz (D) 50kHz

45.

8.<::>

(A) 0.2 JlF (B) 0.02JJ.F (C) 2 JlF (D) 20JlF

46. Match the switch arr ang em ents on the top row to the steady-state v-I ch aracteri sti cs on the I ower row. The steady state operating points are shown by I arge bl ad< dots

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47.

48.

~) - ~) +- +-~

(A) A-1 B-11 C-III D-IV (B) A-Il B -IV

A - IV B - III C -I D -II

For the c1rcu1t shown, find out the current flowmg through theG 1stance. Also identify the changes to be made to double the current g h + he 2Q resistance

(A) (SA; Put Vs = 20V)

(B) (2A;PutV.=8V)

(C) (SA; Put Is= lOA)

(D) (7 A; Put Is = 12 A)

3-~·· ....,~~o.e~Balanced

Supply 4 OOVolts

50Hz ~----~bL-----------~-J~~~

0 (B) 1600 Watt (C) 800 Watt

2.n

c

(D) 400 Watt

49. An average-reading digital m u I tim eter reads lOV when fed with a tri an gu I ar wave, symmetric about the time-axis. For the same input an rm s-reading meter will read.

(A) 20 I .J3 (B) 10 I .J3 (C) 20.J3 (D) w.J3

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50. Figure shows the extended view of a 2 pole de machine with 10 armature conductors. N arm al brush positions are shown by A and B, pi aced at the interpolar axis. If the brushes are now shifted, in the direction of rotation, to A' and B' as shown, the val tag e waveform V A:P: wi II resem b I e

B' A'

rotation at speed ~ rad I sec (A)

0

v •.

(B)

(C) V•

I I O>t

0

(D)

O>t 0.2?t OA" 0.6?t 0.8?t "

Common Data Questions: 51 & 52

N S1

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51.

52.

53.

54.

The star-delta transformer shown above is excited on the star side with a balanced, 4-wire, 3-phase, sinusoidal voltage supply of rated magnitude. The transformer is under no I oad condition.

With both 51 and 52 open, the core flux waveform wi II be

(A) A sinusoid at fund am ental frequency (B) Flat topped with third harm ani c

(C) Peaky with third harmonic (D) None of these

With 52 closed and 51 open, the current waveform in the delta winding~ (A) a sinusoid at fun dam ental frequency (B) flat topped with third h om

(C) only third harmonic (D) none of these 0 Common Data Questions: 53 & 54 CJ

The d rcui t diagram shows a two winding, I ossless flux, excited from a current source, i ( t), whose transformer has a m agn eti zing inductance of 40,~Nf

Q----;1:1 A

t i(t)

B

(C) 320V

where u (t) is the input andy (t) is the output

hm,.a. with no leakage also shown. The

(D)B00/1tV

voltage

(D) 160V

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55.

56.

The system transfer function is

(A) s+2 (B) s+3 s' +5s -6 s' +5s +6

5+5 (c) -s'• .:.+ -'-55.:.+~6

The state tr ansi ti on matrix of the above system is

(A) [ e->~:~-" e~"] (B) [ e~"

(C) (D) [ e~'

(D) 2s -5 s' +5s -6

Linked Answer Questions: Q.57 to Q.60 Carry Two M6 ch Statement for Linked Answer Questiio~1"

A------,

Coill

The figure above shows coi Is n w h dot m ark i ngs as shown, having 400 0

excited with single phase z supply and 6000 turns respectiv~l . h , Is have a rated current of 25A. Coil 1 is

57. The coils are to be o ct to obtain a single phase, 400/1000V, auto transformer to driv. I oa f 10 kVA. Which of the options given should be ex erd sed to realize ; red auto transformer?

(A) Connect A~;. mmon B (B) Connect Band D; Common C

(C) Connect A ~Common B (D) Connect A and C; Common D

58. In t~e · nj'ormer obtained 1n Question 57, the current 1n each coll1s

IS 25 A and COII-2 IS 10 A (B) COII-1 IS 10 A and Coll-2 IS 25 A

oil- IS 10 A and COII-2 IS 15 A (D) COII-1 IS 15 A and Coll-2 IS 10 A

Statement for Linked Answer Questions: 59 & 60

21<1'! 3V••

,--,jL---.--<+ - A

sv • 21<1'!

L----~----L---os

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59. For the circuit given above, the Theveni n 's resistance across the terminals A and B is

(A) O.Sk~ (B) 0.2k~ (C) lk~ (D)O.llk~

6 0. For the circuit given ab ave, the Theveni n 's voltage across the terminals A and B is

(A) 1.25V (B) 0.25V

0~ •

~

(C) 1 V ,,,,,~

uO ,Jo·

&'(j