GATE- Electrical Engg(EE)- 2008.doc

7/25/2019 GATE- Electrical Engg(EE)- 2008.doc

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EEGATE Paper 2008

]Answer keys

1 A 2 B 3 C 4 C 5 D 6 A 7 D

8 C 9 A 10 A 11 D 12 B 13 D 14 C

15 D 16 B 17 A 18 B 19 D 20 D 21 C

22 C 23 A 24 B 25 B 26 B 27 28 B

29 C 30 B 31 D 32 A 33 D 34 D 35 A

36 D 37 C 38 39 B 40 B 41 C 42 A

43 44 B 45 B 46 B 47 B 48 C 49 B

50 C 51 C 52 C 53 54 C 55 B 56 B

57 B 58 59 60 C 61 C 62 B 63 C

64 A 65 A 66 C 67 C 68 C 69 B 70 A

71 72 73 74 75 76 C 77

78 B 79 C 80 C 81 B 82 D 83 C 84 D

85 A

Explanation!1"

(# +n 1)# =$o o% #ran&'esn =$o o% no(es

2"

)t' =*t'

+t' 15"47"8

re%

= 3"71 15"92"4 8"0

)

= 1"54 7"8 *) lea( * so it is a &o,#ination o% -esistan&e an( &apa&itan&e

(t (t

(+ )3" .'en we apply e sin t to /) syste, is o% %or, e sin t

( )so &o,pare t'is eation wit'

4

etsint

+ so = =

4" 3x (x = x4 1 =014

5" )t s'ol( satis%y t'e &'ara&teristi& eation 322l 0

3+2+ (2+ + 1) = 0 2 + =1 0 2) +

( )2 + + 1 = 1 = 2+ +

0 an( 2) + 0

2)

1


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EEGATE Paper 2008

6"

7"

8"

-ank is 4 so will 'a:e %or linearly in(epen(ent &ol,ns an( %or linearly

in(epen(ent rows"

;< s( ) + y s( ) = 1

( ) =1

< ss + 1

t ( )e t=p to 5"7* t'e (io(e is in re:erse #iase( so *0>*ian( (io(e is %orwar( #iase(a%ter *i ? 5"7 an( rea&'es peak :ale an( &o,es to a@ain 5"7* in t'is otpt:olta@e is 5"7* a%ter t'at a@ain (io(e is in re:erse #ias so *0>*i

11" 'eory #it

12"

C

A

B

30


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EEGATE Paper 2008

19" /inear syste, 'ol(s sperposition t'eore,

Casal syste, ,eans 'FtG > 0 %or t H 0

20" )n "C" test p% is low so we se low p% ,eters an( )n ;"C" test p% is 'i@' so wese 'i@' p% ,eters"

;"C"esttest 2k:A=8"69A" so we se 10A,eter 230:

2 1 2 = 6 2 =21" - = 6 C = =

2 + 1 3 = -C 3 4

0"15

( ) + ( 1 )22" = 0"1s 1 s

eatin@ i,a@inary pot to +ero

= 3ra( se&

2

+ 1s

1

23" i = 1A= =

:21 2 2::a#+ :2 =5 0:a#= 2"5 = 3:

A

+

1A :a#

A

+:2:i

12

,5*

624" C = 0 C = 0 = 8"85 10 500 500 10

= 1475I

( ( + 4 103 2 1031

(2

12

(300)2 (

8 + 2

)2$2 A 300 103

25" / = 0 rl 0 r 3 l = 0"3,

26" +5 2i1= 0i = 2"5

300 10

1+

:a# 3

1: = 2"5:olt2"5 + : + =i 0 + +:

a#+i1

a#

= 2"55: +

1 : 1 i

:a#

4: + 3i + =i 0 i1 a#

i = :a#i + =1 2"5

i =2"52

= 1"25

3


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6/15

EEGATE Paper 2008

28" Jint FiG Apply s'i%tin@ FiiG s&alin@ an( FiiiG i,e re:ersal

29" $on!&asal #e&ase t'e si@nal is (e%ine( %or tH0 also ti,e in:ariant sin&e yFn!kG

> KxFn!G] w'ere x n( ) y n( )1

30" sin & t

2 2 &on:oltion in ti,e (,in is F G in %reen&y

sin & Bt

32" (1 +L)n

( )

B 2

J +( )

B 2 so it will #e ,ax (B)

( ) = ( ) ( )y +( ) =

x + + y n

+ (1 +L){ +

}+ 11 L

( ) ( )n ( ) + is +ero %or x n 1 +L an( t'e +" rans%or, o% x n =

( ) 1 1 ( ) +1 1 +L

'e -C o% 1 + J + 2

i,plies it 'as 1 pole an( 1 +ero

n

33" 1

( ) ( )-e si(es o% + "

(

n 1

+

( )(+ a)n

w'ere

( )n(n 1 M (+

)+ a

n = or(er o% pole+ a at + = a

@i:en pro#le,

n = 2-e si(es(+n 1 ( ) ) =(

1 ( (+n 1

( )

) + = a

)2 1 M (+

1 ( ( )(

+2 a)

= 1M (+)2(

+ a

2

34" ( ) = (x2 4)2% x

1 ( ) =

(2

)

= ( ( )(+

+ a =n 1

n+ + a= n 1

na

% 12 x 4 "2x


7/15

(2 ) % 0 4x x 4 = 0 x = 0 2 2

11 ( ) =%

2

12x 16

x = 0 %11= 16 ,ax

x = + %11= 64 ,ax

x = + % 11= 111=0 %

24x

x = + % 111= =24 2 48 ,ax

4


8/15

EEGATE Paper 2008

( )% x

35" xn 1

=xn %

n

1 ( )n ( ) =% xn

xen 1

x1=x0

( )% x 0

1 ( )0%

%1 ( )

n=

x

en

= 1

1e

1e

=0"71828

+ = ( ) 1 1 ( ) ( ) = 136" A A = A A A

A #y &'e&kin@ options1

AA A+= AA A = A AA A+ A+

'37" x = y0+ 2y2

2

x t( ) 139" ( ) =

I s1

( )ist% t e (t

0 1 t

= ( ) ist % t( ) = x t( ) + x ( )1 1 e (t % t( )

= 2 sin &s = 2 sin &2 1 1 t

40" 'e #ot' trans%er %or a &ont ,irror 1k +5; = ) )re%

0)1 re% )1

)1 =0 0"7 0"7 + 5

1

41"

= 3"6,A

:1( ) = :1( ) = 0:at t'e 'al% &y&le a%ter t = 0at : 'al% &y&le : = 5: 5:

+:&1

5:

5

&

5:

&1

+

+

N

:&2:&2

k:/

=10:

5


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EEGATE Paper 2008

42" Co,#ine two wa:e%or,s

:in+ :1

""" 1( ) :in-

-

""" 2

( )

( ) ( )2 ;o A is Answer

44" Jere ,onos'ot opOs 1an( 2'as plse wi(t's o% $an( 0$"

+ :2

1 2

;o w'en tri@@ere( a&&or(in@ to trt' ta#le @i:en 1respon(s toan( wa:e%or, will #e

$1

0$2 an( 2%or

1 0$ $1

% = Dty &y&le = 2

0$1+ 0$2 0$1+ 0$2 $1

45" DAD ;

CJ/

A%ter %irst instr&tion J/ 2700JCJ/so

J/ &ontes ex&'an@e( wit' CC = 2700 ;p = 2700

46" 'e %irst op!a,p is a sare wa:e @enerator an( now a%ter a(Lstin@ :olta@e atP:e ter,inal to 2"5: t'e se&on( op!a,p an %ollows$ow

C

: 2"5 (( 2"5

:0)i - = e at :i

-

1 :i 2"5 = 2"5 *o-C

so trian@le wa:e s'i%ts pwar(

2"5:

47" ; = 1500 1425 = 0"05 e%%e&ti:e rotor resis tan &e = 7"8 7"8

1500

48" Jint &ore losses 1200w are also &onsi(ere(

2 0"05 2 ;

6


11/15

EEGATE Paper 2008

49" Jint Ers = ($ Q

t = 0 to 1 t'e o p :olta@e is :e an( &onstant :alet = 1 to 2 t'e o p :olta@e is +ero

50" Dire&t

:2

/1

2 (t

/2

t = 2 to 2"5 t'e o p :olta@e is + :e an( &onstant

( )1 0"3 /

51" ;)/1 =

;)/

C1

:2= C2

/= C

/= 0"7 ;)/2 =

;)/1

0"72

/21

C1

C

52"

C2

(C1=(C2(R(R

1 2

( )1 + 0"11 R1=30"06 R2 """""" 1

R+ R = ( )250 """""" 2

1

( ) ( )sol:e 1 S 2

2

= ( )2

+ ( )2

+ ( )2

54" -e ,o:e e t'en loss4 +

( )2( )2+ + = 25 + +9 4 = 36+

2

e t'en loss + 111 +3+ + + + = +1 49 + 4 = 54+

;o i% we re,o:e C3t'en syste, will operate wit' ,ini,, loss"

55" Jint % = 2 2

(

)57" E#1E#=220 2"5 20 = 170

10001 =

E#600

E#

2

= 600 170 = 1022 1000

* = 102 + 50 = 152

(ty &y&le =152

250= 0"608

7


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60" st =

EEGATE Paper 2008

2a2

,ax 1 + a

1 =2 a

21 + a

a = 1

-2= 1=0"666x 1"5

61"

2* = 0"66 400 = 266"6*%reen&y = s% = 0"666 50 = 33"3J+

2*,&os = 130 =129

= 2 ( ) = 2 10 3 = 7"862" .D 9 9 = 0"31 = 31 -,s :ale 2

63" *0

=*s

(1

)= 20 = =

40* sin&e poweris &onstant 20 440 ) )((

= 2A

( )

1 0"5 0"5

64" C ;

( )- ;

= ( )R ;

( )

( )- ; = 1

( )/t C t = /t ;C t

x s 0

( ) +65" C

1= 10 ; + 1

( )C

2= ; 10

()

pole

; + 10

+ero

10 ; + 1

10 1

lea( &o,pensator

10 1

la@ &o,pensator

66" At startin@ t'e stop is !40(B(e&o(e At startin@ we 'a:e 2 poles an( in nextportion t'e stop is &'an@es %ro, !40(B(e&o(e to !20(B(e&o(e Fi"e" we 'a:eone +ero an( next portion t'e stop is &'an@es %ro, F!20(B(e&o(e to 0(B(e&o(eGFi"e" one +eroG

otal we 'a:e 2 poles an( 2 +eros"

8


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EEGATE Paper 2008

( ) ( ) ( ) = ( 2 ) ( )

67" C ;

( )- ;

= ; ; + 3 ; + 10

1 +

; + 3; ; + 10 +

( )( ) =3

; ; + 3 ; + 10;3+13;2+ 30; + 2

C"E ; + 13; + 30; + = 01 = 30 13 = 3900 < < 390

( )C ;

2

68" ( ) = n2 + + 2- ; ; 2 s n

n

= n10 2= n20= 1 so &riti&al (a,pe(

69" %y=$o" o% 'ori+ontol tan @en&ies %x = %y = %x $o" o% :erti&al tan @en&ies 2

70" (+ = 500) = BC AD

1 1

(3 2) = (

76" Area pto 5se& i"e" A1+ A2+ A3 = 2 4 + 3 2 + = 13RCi = i(t

( )1

2 2 (t

78" "I = C ;) A B + D

79"

80"

ess =1

*0 =

;C=

Jint *i;C + 1-A

pt ;C T

*0

*i

=C2

=+

1

1

1

-

**

1 (2 C-A)81" Iro, t'e @i:en &ir&it

9


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82"

EEGATE Paper 2008

) = )s'+ )a

15 =240

80+ )a

) = 12Aa

At pl@@in@ t'e net :olta@e a&ross ar,atre resistan&e

is >*PE#E = 2400 12 0"5 = 234 = 240 + 234 = 474:

83"

84"

#

)a2= 1"25 )a= 1"25 12 = 15A-

* = +E ) xas

: = 1 0

)a= 0"6 0

x = 1 90

= 23415

0"5 = 15"1

s= +

1 0 E 0"6 01 90E = 1 L0"6 = 1"17 30"96

85"

%

= 1"17 30"96 la@

)a= 1"2)a1= 1"2 0"6 = 0"72

()a x )2= 2 22 s E%+ =t 2E * &os%t

(0"72 1 )2= 1"172+ 12

&os = 0"79 = 37"73sin = 0"6120

2 1"17 1 &os

E

:%tsin = : )a &os &os = 0"994

xs t 2

E &os%= 1"17x0"79 = 0"924E &os%< *'en&e I is 0"994 la@@in@

GATE- Electrical Engg(EE)- 2008.doc

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