C.S.E. Electrical Engg. (PRHIM.)-2005

C.S.E. ELECTRICAL ENGINEERING-2005

(PRP.IMINARY) Time A /lowed : 2 /w;" " Maximtlllt M(trkH : 30U

-----~ ... ---- I.

2.

3.

~~Dr[)----x ... 1_. CJ

If the inpnllO dw :C

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4.

$.

(d) (P+Q) (lhS) If all the messages of a source have the same prbabiliry P, then the source entropy H (m.) is giv~u by (a) -log P

p (c) l - p

(b) +log P 1- p (d) p

.

:.;...._,.:....._:_ "' J3 m; ..:..~~r..AM) 6. To transmit N Signals,

TDM, will require a to f,. by : of

7.

(a) fm Hz (c) Nfm Hz In 3 DM systeflf anular noise occu" when the modulati;.eg (a) incre rly (b) increase-S exponentially , (c) re~ nst.ant (d) decreases: rapidly

8. Consi t follwoing stl.'temcnts in connection with: P s. s ern: :

Ct\'4 is much better for noise immunity as it depends!

g1ven llme. 2. PCM requires a small bandwidth C{)mpared t~ analog;

systems. 3. P.cM.requires very

when it comes to noise performance. "Which of the statement given above are correct" : (a) l , 2 and 4 (b) I, 3 and 4 {c) 2, 3 and 4 {d) l, 2 and 3

I. The frequency spectrum of an amplitude-modulated signal contains

10.

11.

(a) canier frequency only (b) sideband freque ncies only (c) mQdulating frequency only (d) carrier and sideband .frequencies

maximum amplitude A,n and a minimumet A,;a (a positive value), then the mo-dula on ex is given by

(a) A,.., A.,...

(c) A..,.,. - Anun A...,.+ A,,n In

(b)

of the fourier }ftnon of Time) with List-

and select the correct below the Lists :

Ust-11 I. IF (oo) I

2.

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c j (t) ~cos UJo t a. l F(w)

- we ~ :t :

O ~ t 'V 0 (!):'\ ~ ;! --} \\1

D. 4. r f(t)sin wat

r: !F(WI -/1(\h/1 LJ A .-- _ _l_ V\:{()U -

r ~t ~~U C) I A B c D A t,eJ (a) l 3 2 4 (b) 2 (c) ! :1 4 2 (d) 2

12.

..rg I'ourier lra n c gate function as shown ahvc is f(t) :: l :'2 ' l i ti2

:; () ' . r tse

f J,u .. of l (11>} 1S " ( \..r

~.

14.

1mA

-

1K --ANII'v-

... sv

working with -t 5 v and -5 v p{)Wf)f supplies. To voltage V 0 is eq u.aJ to {a) + 5 v (b) + 1 V (c) - 1 V 5> V

+ 15V

- 15V

10~n 10kn -

The cin:uit giv is (a.) peak detc o (b) Schmitt trigger (c) buffer (d) u nity gain amplifier

15. Match~ Scheme o{ Feedback ) with List-11 (Perfor e . easure) and select the correct answer

th od e g iven below the Lists : Utt~l ListII rrr

ou!put impedance increases D. Voltage Stlunl 4. Input impedance decreases,

output impedance increases A B c D A B c D

(a} :~ 4 2 I (b) 2 l 3 4 ({:) 3 4 2 (d) 2 4 3 1

HL

v,., sln c.~t

(a) 50rt

(c) v

"' . ~:::r

17. Th \~ f.H~r llr.J i l imp

{C) 030 (d) 060

d

d

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19.

:w.

21.

A bunlcd conduc10r has 3 conductors, equil

21.

25.

2. Ho!Or is providecl with narrow slots embedded with bars.

:5. Tor(jue at swning is :some wh

List-1 A Capaciwr-run

motor

') ~ R Capacitor-start

end run motor

C. Shaded-pole motor

D Resistor-sp!ir phase moter

A (a) 2 (

3&> C.S.E. Electrical En.gg. (PRELIM.)-2005

2X.

29.

I r.c;)

s (d) I - S s

To prC\'Cl1t th~ shift i n~ of the magnetic n~utr~l axis, (:

:n.

(a) be proportionate to their percentage lmpc!danees (b) be independant c>f their pen.:entage impedanC(!S (c) he !nvcrs.ely proportional to their respc

(h) R(s) ~ ~~ A(s) I -r ln(s) IE

~H(w) l A I ~ 1

(d)

0

1 I

C(s} )

C (s)

+ 1

-l

I H(

35.

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s ~ (ll ;--;: s What will be the output voltage if the i11put voltage is b(t) ? (a) ,fi si11(61 t ... l't / 4) (b) cos (j)(- sin u)t (c) co~ wt (d) ..[2 si n(l:lt t r. /4) ~!l. Whkh f the following characteristics of th~ sys~ arc ddmed by y(t) = x(t> Cs (1 OO~t)? L h is linear. :2. It is time invario - . ~- h ~s causal. 4. 1t is

41.

c.

D.

j (l) .+.

I -++-~ l ; 0 j w

i ,.. ;)-A

(a) 2 (C) 2

B C 1 4 3

0 3 4

3. g(t)

1 .__..-'-------~(

4.

x.l(j.or the networl< shown above ? i r,. ~ r.. u

'-') i : .. .

r + r ~ .

' .. , .. __ ,._.

r" ~ r:: j

,..---~ 6 0 0 0 c -! v ... 50cosc~t + L

-.., 5 )2

---

lo r t ll'l ilhvt:, if GO\\'

45.

46.

Fbr lllc above c ircuit, if the .current 1=:~ t\ and 15 A for R1_ = 0 and 2 D respc

48.

50.

1---f

~

X y Tht\ output f of the

51.

52.

53.

The circuit i n the figure given above has two

57.

58.

5~).

60.

What is/are the di:sadvantage(s) of Gauss-Seidel mthod over Newton's method in loadflow prog:ra mmes "! (a) More iteration (b) Mor'c rncm

61.

10 A I 1 1 .. I

0 T/2. T ~':"' 2

62.

A MOSFET rated for 20 A, carries a periodic current as ~ shown in the above figure. The or1-slate resistance l)f the MOSFEf is 02 ohm. What is the average on-state power loss of device per cyc!e : . 0 (a) 20W (b) i5W CJ (c) lOW (d) 5W

0. l'v.,CJ

(bl 180 (C) 200" ~ (dl 240

63. Match Li ' h List -II and select the correct answer usin the e given below lhe Lists :

.!st-1 List-11 . verter) (Application)

factor ~ B. Hlflled ooo"rt" 2. Soft"'"'""'.''

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li5.

motor C. :!-phase a.!

AB CD AB CD ~ (a) :l l 2 'L (h) 2 4 5 (C) :\ -~ 2 l (d) 2 5 4 a \Vhi

0 to rated value. Which one of the followi.ng statements is corrocc:t? The torque developed by the motor is (a) proportional to speed (b) proportional to square of speed (c) inversely pn>portionai to speed {d) constant in the complete nmg~ up to base speed

l)irections : The following 6 (six) items consist of two statements; one !a belled as the Assertion (A) m1 the other as 'Reason (R)'. You are to examine t two statements carefully and select. the msw'

---these items usin.g the code given below: (a) Both A and H are indiv[dually rwe a1,...,......,

correct explanation of A. (b) Both A and R are individually tnw but H

correct .explanation of A n. + (c} A is tme but R is falstahlt: botH sluggish system .

...._ ~ A.r;;serlion (A) SiC!1 is added to Cl 2 in order t

Reason {R)

70. Assertion (A)

Rea~on (!{)

71.

Hcas()n (I{)

n. .-\ sS(:.rtion (A}

Ht~aso r.l (U)

110 isorropica!ly. Cl2 etches aluminium while SiC!. etcllcs native aluminium oxidf; and also provides ~nisotropy by forming sicl~wall inhibit

75.

76.

77.

B. s2 + 24.s + 225 "' 0 c. s2 + 2025 , 0 D. s2 + 20s + t OO = 0

A B c D (a) 1 3 :2 4 ((:} l 4 J 2

2. 3. 4.

(b) (d)

Underdampetl Critically damped Overdamped A B C D 4 3 I 2 4 2 :.!

Given the m.atrix

ro '

1 0 A~ lo 0 1

I \-G V ency. l. For stable sy~tem:S, tile grs\. "S vcr frequency is

:.!. For lJOstahte systems .~e cross-over frequency is greater than ph a '-' sS

79.

so.

system. which one of the following control wm be empl{)yed ? (a) cascade PO (b) Cascade PI

s-chemes

(c) Rate reedba

81.

&2.

(b) ll.I -, towards the conductor 41t"

lA [2 (c) ~;log, 2 away from the conductor

(d)

The magnetic~ tentia! at the point I-' due to the current 1

85.

valu~~ (b) the tangential magnetic fi eld components are

continuous (c) the electromagnetic wave is reflected back according

to Snell's law (d) the clectromagn(~tip.oHoly., >how" . Wh"

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86.

is lhe impedanee m easured a t the end XX? (~ R O 4R (c) Zr/fR (d) 4Z.o/R Match List- ! (.Expression) with List-.IJ {Coefficient) and s>Ciect t hc correct a nswer using the code given below the Li sts

A.

B.

D.

List I (Expression)

Z ,., .. 1. ' " '(I p ~' ;::""'"""";: ... z., . ... z~

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Circuit/Rectifier) with Ust-11 (Type of Clipper/ l~ecti{ier) and select the correct answer using the eode given below the Lists :

List! (fransfer Characteristics

of Clipper CircuittRectifier) A. l.

Vout

-~:....--~ Vin

List-11 (Type of Clipper! Rectifier) Doubled-ended clipper

2. Positive clipper CJ n. --.,.!'---~ Vin '(J

Vout

c.

_/

Vout

D.

~ /\ l3 c

,t) I 2 I

J)

fl>CJ ve clipper

Full-wave positive rectifier and no: a clipper

8 -.

.)

3

( 4 I

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89. Consider the following circuits; R v ldt:al

; I

!den! t---1~ I ; i iJ Vo R~ Vo I ' /.. u, t VI

* L l * ldcaJ

f r vi l 3 ! R I 1'

Which of the following circuits ~~ t: e following input-output characteristics ~~clipper ? v o = v, for v; < V fJi

= V for v. > V ~ Select the cor;ect an~wer us co e given below : (a) 1 only .l} !y (c) l and 3 l , 2 and :3

9Q. By addition of s~ nt or which one of the following ca;:pne or Si02 in IC fabricalion be improved ? (a) Boron (b) Chlorir.e (ci Zirco'Q ._ (d) Inc!ium

!H. Consider ~!lowing statements: l~one process is u~d for refin ing Si from s having segregation codficien t K < 1. The held vertically and the zone is moved from

ottom to top of the ingot. After each run

and is to be cut thrown bd

H.2.

n:~.

2. the bottom end of the ingot contains maximum inpuritics and is to be cut and 1hrown before th(~ next run.

3. there is no need of cuning the bottom end before the next run as it cont"ains minimum impuri ties.

Whi.aatemcnts given above is/an; Whi~:h_ h _statcrnetm giv-e~ a~)ovc iS.fare correct'? ( 2. , 5 (b J 1 and '2

iy (d) 2 on!v f der the folll'rWi IJ1: st;~lemcnts:

~~thod

2. the seed crystal should be p1JfC and dd~~ct free for high quality growth.

:3. in ten tionally doped single crystals cannot IY~ obtained by this technique.

Which of the statements given at)ovc aoe correct'? (

96. Consider the following statements ar;"-fs: i. Ferrite:; have high resistivity. 2. Ferritcs have low eddv current~ . 3. Ferrites are used as core m

(c) ionic polaris

103.

according: to Pauli principle (c) The ;otal number of pos.sible wave f:Jnctions in any

energy band is equal to the total number oi free electrons :n the band

(d) The number of possible wave functions in any em~rg_v band is independent of the number of unit wiis

104. While m~n the value of distributed capacitance by Q-mc h esonances were obtained lA ith values of t lng dtor as c, and C2 for the frequencies

d ~ f1 and 2f1 respectively. What is the

..._ ~ C..r2~~c distributed capa;it:~~;;~.? ~~~) '-,--- (b) '

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I 05.

lOlL

'' - ''(' ectivcly, what is lh() rcadjng of Al ? {il) ~ (\ r ~ (h) 3 A "-J tel !) ;\ ~

107. \\'hil"''l.l1 a coil havint; a rc_sista nce of I i l, rt~so tl; ccu rred wh(! n th{': oscJllatr frequency ~\ 1.0~ J. and the variable capa ci tor was set at

~~' pt. What is the effcdiv

108.

c,.. {unkno v.Tl)

C -E- s~andard capa-citor

109. A resistance is measured c tmctcr-ammeter method. The voltme te r re :>0 V on 100 V scale and ammeter reading i. 'i

ll L t\ ;;5 V d. c. ~up ply is con netted acro:;s

117. Consider the following: 1. Small ~apa.' . re separately in the main memory? l . lndin~~~t 2. Immediate 3. Index S elect ~ ct a nswer using the code given he! ow: (a) 1, n a (h) 1 and 2 ~" . (d) I and 3

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