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TRIBIILIV ;'rlJ I iNiVERSITY
I}iSTITUTE Oi. I\CINEERING
Examination Control Ilivisiori
2$?8 Bhadra
Subject: - Elecro-magnetics (EX 503)
Candidates are required to give their answers in their orra ltords as frrr as practicable.
ltte ntpt A I I q it( itions.
'{he figures in ihe margin indicate {S$ Wt'Ls_.
Necessary dfitij a_re a{tached hgls-t+,itk.
,d represent a vector and d*6rrr1rs denotes a unit vector aiong the .lirection given by the
subscript.
Assume suitablc dota dnecess*ry.
i. Givenapoint P (-2, 6, 3) and vector field E= yd+ (xy+z){, express p and E in
spherical co-ordinatb system. t5]
2. A point charge of 6pc located at origiu, iiniforro iinr charge density of 180ne/m lies along
x-axis and uniform sheet charge of 25 clmz lies ol z:0 plane. Fhd d at point (1,2,4j. tI
3. Derive the expression for an eiectoic field intensity due to an infinitely long iine charge
with charge density p1 by using Gauss's law. Find the volume charge riensity that is
associated with the field D = Eyzdz + x"yd, + zAz C /rnz. [4+j]
4" State ccntinuity equation. Given the vector cr.urent de;isit1,
i = 1Ap2frp-,lpsrnz$d6 mA/mz. tretermine the current f<.rllovriirg outrvard the circular
band P=5, 0< $<2n,2<z<2"8. 12+41
5. Differentiate between scalar magnelic poiential and'.'ector magnetic potential. If s vector
uragnetic potential is E= -(5ziqdrwb/m, c*lculate totai magnetic flr:-x crossiag the
surtrse $=n12,1 Sp57- rn andO <z<5m. [1+4]
6" Tlieregiony<0 (region ii is airandy> il iregion2) has pr,= 10. if there is auniicrm
rrragnetic field H = 56x * 6ey + TezA/m in region 1, find d and }j in region 2. t8l
7. Conect the equatioa V x E = 0 for time varying fiel<i with necessary derivation. Aiso
modify the equation V x H = oE *itl, necessar-v arguments an<i deiivation for tine
varying field. [3+4]
8. A unifnun plane wave in lree space is gir,"en by rts=(ZSAz.30o)c-i3s0zd.*V/m.
Determine phase constant, iiequerrcy of the *'ave, intrirsic impcdance, .E-. and the
magnitude Eofat z:25mrnandt:4ps. [i+1-2+-:'-i]
9. Derive the expression fsr eleciric arrd magnetic fieids for a uniiorm plane rvave
propagating in a free space. iS]
10. A lossless transmission line i-s 80 cm ic;ng aird operates at a iiequenci l GFIz. The line
pararneters are L: 0.5 pi{im and C : 2ilii pFlri}. Find the chr.ri".jiriisiiits impedance. iLre
phase cons'"ant, the velocity r:n the line, and the input impedance fo,. Z1 = 100Q. l:r)-;: { 2
ii. Writc short notes on TE and 'IM rnock;s of rectangular r,,,avegtrirle. An air fiii,:r-L
rectangular rvitr',.riluidc has crirss-sectioii .of 2.3 cnr v. 1.t-: ril;1. Ualculate th? ctli-,it
frequency af the daminant mode (TEto)"
12. Write short notes about antenna and its parameters.
[3+3]
121
,.* -*
Exam"'
I-evel BE Fult Marks i 80
Programme tsEL, tsEX, BEl.
BCT
i
Pass Marks: 32
Year / Part It tI Tirne , i trrs"
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pfe
pff
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TRIBIILIV ;'rlJ I iNiVERSITY

I}iSTITUTE Oi. I\CINEERING

Examination Control Ilivisiori

2$?8 Bhadra

Subject: - Elecro-magnetics (EX 503)

Candidates are required to give^ their answers in their^ orra^ ltords^ as^ frrr^ as^ practicable.

ltte ntpt^ A^ I^ I^ q^ it( itions.

'{he figures

in ihe margin indicate

{S$ Wt'Ls_.

Necessary dfitij a_re a{tached hgls-t+,itk.

,d represent a vector and d*6rrr1rs denotes a unit vector^ aiong the

.lirection (^) given by the

subscript.

Assume suitablc dota dnecess*ry.

i. (^) Givenapoint P (-2, 6, 3) and vector field E= yd+ (xy+z){, express

p

and E in

spherical co-ordinatb system. t5]

  1. A point^ charge of 6pc located at origiu, iiniforro iinr charge density of 180ne/m lies along

x-axis and uniform sheet charge of 25 clmz lies ol z:0 plane.^ Fhd d at point^ (1,2,4j.^ tI

  1. Derive the expression for an eiectoic field intensity due to an infinitely long iine charge

with charge density p1 by using Gauss's law. Find the volume charge riensity that is

associated with the field D

Eyzdz + x"yd, (^) + zAz C

/rnz. [4+j]

4" State ccntinuity equation. Given the vector cr.urent de;isit1,

i =

1Ap2frp-,lpsrnz$d6 mA/mz. tretermine the current f<.rllovriirg outrvard the circular

band

P=5, 0<

$<2n,2 il iregion2)

has pr,=^ 10. if there is auniicrm

rrragnetic field H (^) = 56x * 6ey + TezA/m in region 1, find d and }j in region 2. t8l

  1. Conect the equatioa V x E (^) = 0 for time varying fiel Divergence

cartesian:v D=$p-{.

AxryAz

cylindnca I : v.^ D =

I

a(dD')

1+

p op poq^ sz

.. .- .: 1 f(r2D,)^ I d(D"sins)^ I^

&+

Snhecncal:.lJ= +-_

'--+_--

r' Ar^ rsin^0 eS^ rsin^0 d$

Gradient

carresian, vv^ = s 6,^ *^ *a. *^ *a"

dx6y'az

cvtindrical: vv=9l4, *

1 9Ia. (^) * {a-

0p

o p0{l

Az

av^ Iav. l av^

Sphericai:Vv"* (^) =?6, +:iia. +--:

6 r 6J rsrnu =i-irdO

Curl

c-artesidn:vx fr =fgrr.-

aHi

L -l.g.-fl.]a

.,.[5r.- tr ],

(0Y Az)'taz ax)'\Ax AY)"

cvrindrica r : v. fi

f

9!.

3L'lu *(

Ht

au

"L. *^

lf

'ot'o

4"..|u

'

\ea$

0z)'(az 0P)' P\

0P Ai)'

spher'rcar : V x s

=

I

=[LEtrr

e)

  • +].

.

1f+=+

g'H,

+.

lf

q('9,

  • 9,

).

,re[--aol-- a+ J"'";L'*s

aS

n, f'

*;[

a'

n (^) )".'

Laplacian:

Cartesian:VzV= (^) ++*

oNL dy. oz"

cyiindricar: vzv

i*(rffi

i#-#

Spherical: vz\r

= i* i" ffi

#*fd

(',ru

iii

.

i0. A 50 f) lossless iransmission line is 0.4 l" long. The line is terminated with a load

Zt:4A +^

j30 A. If the

operating frequency is 30il^ MHz,^ find^ [2+2+4)

a) reflection coeflicient (f)

b) standing u'ave ratio (s) and

c) input i:npedance^ {Z*)

ltr.Explain why TEM-wave doesn't exist in a rectangular waveguide? A rectangular

waveguide has^ dimensions^ a^

:

1 er& b

:

crn. The medium within the waveguides has

€,

: 1, lrr:

1, o

1. Find whether or not tlle signal with^ the frequency^ of^500 MHz^ will

be transmitted in the TE1,6 mode" [2+4]

  1. $lhat are the parameters^ of^ anterura? List^ out^ the^ different types^ of^ antenna^ you^ have

studied. [1+l

j

Divergence

  • 6D^

AD' (^) AD-

Cartesian : V. D (^) =-3 +^

=t

*-

0x AY Oz

I

r6(pDo).1dD0,0D,

CYlindrica I :^ V'^ D =

:

-=--

T --=-

T -;-

' p (^) dp poq oz

.,-i l8(r'?D") I^ a(Dssin0)^

I 6Dr

spnecncal: r"^ u=-T-*6.-^

" r.rB- A

**irin

gE-

Grailient

av^ av^ av^

Cartesian:VV (^) =--O* -a^ *---^d,

AxaY'02'

cylindrical : vu

= $

a, *

!*a,

*a,

o? poq^

sohericat:vv*9Ye.

lav^ I av^

  • & '^

*;H uu *iiln;6:",

Curl

t^'{, oH, )".

(au- (^) oH"f. ,

(au, (^) oH- l" c-artesian'vxfr=l

al' *' !a- "ir

-***o

ur!L)I4rr'"^"-l lu,^ +l^ i-r-gi"^ la,

a),

a,

j"' '[a,

-a*

f'

-l

a" f'

cyrindricar:v,r=[;

r+

E )"r.[.a,.

-?#f (^) r.'

;LTp

(^6) )n,

sphericar : v x^ fr (^) =

-r*

[

aG.:in ol

  • +],^

-. {'-l

gL

a(:ur )lu"

  • l[

u(t,

  • tL^ lu,

'si"e[

ae

a[f'

' i\rsirie a,[ 0r

J-u

'

tl. ar &^ )

Laplaeian:

carresian: v2v^ =

#,

#,

-#

cyiindrieah v21I =;*(-#)

*,#ii

spherieal: vzY

i*(.'11.)

ala('r#)

TRIBHUVAN TNIVERSITY

INSTITUTE

OF ENGiNEERING

Examination Controtr (^) Division

2076 Chaitra

:

gl (^) gg[g-gagjl{[! fsx -i o-ii

/ candiiiates-are required to give their zurswers (^) in their or+:r (^) rvords as far es practicable. t

Atrcmltf Att qttestions.

{. The figures in^ the^ mnrgin (^) inrlicate Full.ltf (^) arks.

,.

"

-lsstintc ,tltit,iblc ,in;o iJiiiliSl-- Unecessary. $I'','i;,*ii1. , ,

-;tffi

_)

?Hm;**l

s

1' (^) Transform the (^) vectar

A

46x

-2ey

*-4ez

into (^) spherical co-orclinates ai a point p(x = -2.

Y

: -3' z': 4')'

lsl 2' (^) An intinite

uniforrn line charge

pL (^) - 2nCrm lies alcng the

x-axis

in fr.ee space, rr4rile

pointcharges

of8'Ceacharelocatedat(0.

0, 1)and(G, (^) 0, -1). (a) Find (^) il at(2,3, -41.

t6l

3" (^) Dbfine uniqueness theorem" Find (^) the energy st.red (^) in free space (^) 1br rhe region 2mm< (^) r< 3iir*r, 0<0<90", 0<0<90", given

thc potential^ field

\r

: , =-*-'

'-'

1MrL

r! (^) r;'v

'vrwrtrroi

ltsru \ - :

l'2*

a) --\r erd (^) b) alcosOy

4' (^) using the continuitv (^) equation elaboi:ie (^) tire coirceiri

cf

Rela:taiion Tirue constant 1RTC)

with nccessary

derivaiions. (^) Ler ;=+- (^) ;,p

Atm2bc rhe cunent

censity (^) in a given

r, Y

region' Ai t: (^) trOms, carcurate

tire arnouni of

current passing through (^) surface p:2m,

00 (^) (region 2) (^) has

Fr

= J

g'

Ifthere is a unifonn

magneric fierd d= (^) 5i* +66., t.75,rNmin region (^) 2. rrnd d

and (^) H in region 2.

12+6) ?- (^) List

out the Maxwelr-eqrrations phasor

forrn for

tim-e varying

case (^) in &ee space. (^) A conducting bar (^) ean slide

fieeiy over two

conducting (^) rails placed at x (^) = 0 and x :^ lgcm.

calculate (^) the induced (^) voitage in the bar if the

bar srides ai

a velocity 3=16agm/s

and

B,=3izmW-h/m

[2+3]

<:

DIVERGENCE

.ARTESTAN v.D^ =

-Y:-

.YLTNDRT*AL o.,^ =|fio

q"l#+*

spHEBrcAL v-o=jflrrr,l*$$(Dpsino).##

GRADIENT

cARrEstAN on^ =#^*#r#'=

ay .Jav^ ,dY

CYL|NDRICAL vV

=?ap+|"0*^" ap'u' pW^ 0z

sPHEBTcAL

on =ff,,l#**#",

CURL

.ARTESTA,N v^ x r{^ = (* -Y)",.

W-*)r.

(*

\

a.rr,.

3y

cyLrNDRrcAL v^ x^ H^ =

G#

-'#)",. (* - #)"

FIBP=I/')

-!!e)"' pL (^) eip da )

spHERrcAL v^ x^ II^ =#

[,(ffl

-W)".itL,*W-ry]"

*ilvy-#7^r

LAPLACIAN

cARrEsrAN v,v^ =ff+#"#

cvLrNDHrcAr-

tr =iAffi

-*#.#

SPHERICAI.

n:i?#).h(,#) .##

TRIBHIJVA}'IUNIVERSITY

INSTITUTE OF^

ENGINEERING

Examination

Control

Division

2075 Ashwin

Exam.

ffit"l

BEL,BEX,

BCT

I

Pass Marl$

I

80

1?

Ixvel

Programme

Year / Part

cs Wsas!

,"**u".esarerequiredtogivetheiranswersintheirownwordsasfaraspractica

{ (^) AnemPt$lquestio'ls'

,

'rir'iffi

in the margin^

indicate (^) fq!'-Ma*r

r (^) iiiriro*

"n

t (^) Rurrre suitable

dataifnecessary'

I. civen

pointsA(p = 5,^

q= 7a',-z=-3)and

B (p^ 1

2'Q=;s^0" z=^

l)'find:

(a)

a unit vecro,^

m .lrt.iiun^

coordinares

at A directeil toward'B;

(b) a unit vector

tsl

in .vtinari.ut^

.ooiainu"t at^

A directed

toward B'

z. Two uniform^

line charges,^

each z^

nc/m, are^ located^

at y = 1,^ z^ =

t1 m' Find

the rotar^

.ru.oi.hio-i;;;ffi&.

surface of^

a sphere

having a^ radius

of 2 m,^ if^

it ir.uitt'oJi'nir'

1' 0)'

e' u^ e'"r'-^ -^

t6l

  1. ';*;Energy^

Density in

electrostatic^

field'

t7l

  1. The conducting

planes 2x^

3Y = 12-^ and^

2x

  • 3Y

18 a-re:t

notentials of^

100

v and 0, respectivery.^

Let r^

ro rno^

ii,rlill v^ i,^

p (5, 2, E);i)^

E at P(5,2,6)'^ I7l

S.LetafilamentalycurrentofsmAbedirectedfrominfiniwtotheoriginon

thti positive^

r.iil;;;:;b'.k;;;;";;;G

;;ih'

positive x^ axis'^

Find H^

tsl

at P (0, 1,0).

  1. stare Anrpere,s^

circuirat iaw.^

t et^ the^

perrnittivity

be (^5) uH/m

in regiott A

whetex<'O,.and

pHAn in

"gion

Ei*f"tu i

'

o' If^ there^

is a surface

culTentdensi.ryK=150av-ZOOa'n'rmatx=0'andifHl=300a'-400a'+

500a,tum,

find:. (a)^

lHuh

o) lH"J(";li*r'

to HNel'^

[10]

  1. srate and^

explain tJre^

Maxwell'S equation

in^

differential

and inteBral

form'

Also define^ the dispracement

currenit*JnJ;dih

;f

penetration.. [10]

s. Establish^

the relation^

for Helmholtz's

equation

for electromagnetic

wave

tsl

propagation.

_ .. r- ^L--_^-

tol

  1. State and

prove Poynting's^

theorem'

  1. AloadZr =^
  • jl000islocatedatz=^

0onalsssless

50-0 line'The

operating frequency.is^

208 MHz,ai^

ii.*uu.t.t

gth on the line^

is? rn"

(a) If

the line is^

1.ti m in^ length,^

ur* ttr.'i*1i1,^

char tJ find^

the input^ impedance'

(b) whar i,^

"'i;t'dhui

ii rr,.^ distance^

from

the }oad to^

the nearest voltage

t?I

maximuri?

11un.o-'o*orectangularwaveguidehasdimensionsa=.2cmandb=1cm.

Determine

the rangE.of

frequenci.;;;;;i;i.tt

tf'* guide^

will operate single

t3l

mode ftEro)

[3x2]

  1. Write^ short notes

on:'

a) TE^ rnode^

and TM^ rnode

b) Antenna^

ProPerties

TRlBHUV,4N LTNIVERSITY

iNSTITUTE

OF ENGINEE,RING

Exaruination

Control

Division

2{}?5 Chaitra

--;tPt::{:Esryes*sli

cs (EX^ 503)

Candidates are

required to^

give their answers^

in their^ own words

as^

far

AttentPt

All questions'^ "ii*is,r;; ,, t,-..r

in the ruargin^

indicar.e F$tMs'rk*

Tsun* tuitable^

duta if^ necessary^

r

'iirirr*, ^

tkat the^ Bortt^

Faced letter^

represents a^

vector d/?cz^ a5pr561ip

t7l

L1l

vector.

l.Findthevectorthatextendsfrom4(-3'-4'6)to8(-5'2'-8)andexpressitincylindrical (^) li+

cocrdinate 5115{1:6'

rr :- t ''--+^'t (^) '+

+t1a

^ri(

cliarges are^ locate0 is characterized by

zvz:2'LerD1:-30a*+J0a'+70a

'nClnf

and find:-

-^

a) Dg(Tangential^

cornponent of^ D^

in Region 1);

t

b) Polarization^

(P1);

"j

p,, O"""al

component

of E^': Region^

il

grti*gential component of

E in^ Region 2)

  1. Derive

the Possion's

and Laplace's equations'

Assuming,

that the potential^

v in^ the

cylindricai

"ooraii.ui.

;rr.*;r

rh* #;;;

of 'r' only.^

solve the Laplace's equation by

Integration

Vf"tiroJ

uo derive^ ,ir"^

"rpt.ttion

for ihe^ capacitance^

of the Spherical

capacitor

uri,g d;;^

solution of^

v.'"^"""'"

[2+5]

  1. Derive^

the equation^

for magnetic

field intensity

in different

regions due^ to^

a co-xial

cabte carryins^

,;;if;if'iirt

iurr.d;;;;;,

I in the inner^

conductor

and -I

in the

t6l

outer conductor'

  1. Finc the vectcr magnetio

field intensity^

H in catesian^

coordinate

at P(-1'5'

-4' 3) caused

by a cunent frru*."nt^

of 12A in^ the a,

ai'""ti*

on the z-axis and^

extending fi'om z=-3 ta

I6l

z=3.

  1. Define curl^

and giYe^ the^

physical interpretation^

of the^ curl^

with a suitable

example' [1+3]

B.Auniformplanervaveinfreespaceispropagating'".n:-,1,.u'rectionatafrequencyof

MFIz. If^ E=^

cos

(tot+By) a,/lm','t'rite

the expressions

for electric and^

magnetic

" (^) fields, i.e., E,^

(x,y,z) and^ H.^

(x' y'^

'l '"'pt"ii;"il^

ir:.;il*or forms'^

'

[3+5]

g.DeriveanexpressionforStandingWaveRatio(SWR)indicatingwhereonthez-axis

you,ll get^ the n

ax"i-mu*

a irrioiui'"-oi

"f""toit

held intensity^

E' Assurne that the

boundary

i, at ;;th"^

,*gi"n z<0 is

p-rr* ai.lectricand

the region^

z>a may be^ of^

any

tgl

material.

!

10. Find the^ ampiitude^

of thc displacement

current density in^ an^ air^

space within a^ large

--

;;;;";.f;rrr"rH=trj6cos(3?7t+i.2566x

10-62) *rNm. t6l

1i" A lossless 50-f!^

line is 1.5l,long and^ is^ terminated^

with a pufe^ resistance^

of 100fi' The

load voitage is +olr8"v.^

Find: (a)^ the^ average^

polver delivered to^

the ioad; (b)^ the

magniturie of^

the min'-rmum voltage^ on the

iine' [4+4]

  1. W,hat^ are^

the advantages and^ disaclvantages^

of *'aveguides-when^

you compare- it-r'vith

transmission lines?^

Eipiain the transverse^

electric (TE)^ and transverse^

magnetic

(TM)

[3+3]

modes used in rectangular waveguides'

1-:. Give the definition^ of^

an antenna and^ explain^

the properties of^ any onff^

type of antenna

rhat you have stu t*

  1. The velocity of propagation (^) in a lossless transmission line 2.

m/s. Ifthe capacitance

ofthe line is 30 pflm, (^) find: [Z+Z+2+ZJ a) Inductance of the line b) Characteristic impedance c) Phase constant at 100 MHZ d) Reflection coefficient (^) if the line is terminated

with a resistive load of 50Q

I l. What are the advantages (^) of waveguides over tansmission

lines? A rectangular waveguide

' has a moss-section of 2.5 cm x^ 1.2 cm- Find the cut-off frequencies d dominant mode and TE (1,1)

  1. Write (^) short notes on: Antenna properties

[1+4J

l2l {:

DIVERGENCE

Oartesian: v.il

* +^

93 aLk

dx 0y 0z

Cylindrical: v.D =

]{P

1g*

p (^) op poq (^) oz

sphericai: v.d

#9I9fi,9.

GRADIENT

cartesian: vv^

=xd

#q

cyrindrical: vv

Hq+

l"#eo,

Spherical: Vv^

ffa;

i#a;

##a;

LAPLACIAN

cartesian: v2v^

azv ozv ozv

ffi- ayr- fu

cyrindricar: Yzv^ =;*(t#)

##+fi

Spherical :^ vzv^

=

i,V H #*('i"^

efr) *

CURL

Cartesian:

Cylindrical: V^ x^ H

Spherical: V^

x (^) H

vxr

:(*-T)ai+

(#-*)E+ffi

-T)a

=GW-Hq+W-Har+;eP -#)e

==

;fo

(es#

_

fi')

e? +

i ffiiff

_

#)ad

i(ry-*)q

*d< *

',.*

10. A lossless line having an^ air^ dielectrie^ has a^ characteristics impedance^ of^400 O.^ The^ line

is operating at 200 MHz and zi,

=200 -

j O. Find (a)^ SWR (b)^ Zu^ if^ the^ line is^ I^ m

long; (c)^ the distance from the load to the nearest voltage maximwn. 12+4+

I l. Differentiate between transmission line and waveguide. A rectangular waveguide having

cross-seclion of 2 cmx 1 cm is filled with a lossless medium char4cterized by e = 4eo and

F, =^

I. Calculate the cut-off frequency^ of the dominant mode.^ t4+

  1. Write short notes on antenna and its properties- t?l

DIVERGENCE

CARTESIAN

CYLINDRICAL

SPHERICAL

GRADIENT

g.5=oD'

*aD' *oD'

AxfuAz

o.D=L

uobr).;#"#

v.o=.!(,,o-\n-

I a('illD').-:

  • -y 12ar\

-rt rsin9 Ag rsin90$

CARTESIAN

CYI,INDRICAT-

r;Pt iliRtcAL

CURL

0v" av^

-a

r+

oy (^) -a_oz

tav^ aY-

+-a_

pod' oz

raY^ |^ av^ L--^ .L--n

r O0"o rsin? 0,1"c

At/

vv

=+a,

ox

all

^ vy (^) --d

cp

av"

vy:-a,

or

cARrEsrAN

""

o

=(+-+),,.(+

T)r,"(*-+)^,

cylrNDRrcn L vzH (^) =(1an' -a!t\u

.{9!--gg-.)a..rf

a('?H')

-9!r)u.

\p

ad oz )""

' a" ap )"' pl op

a )

cARTESTAN s'e,^ =g'{ot{ *Ef,

&2 avz 022

cYLTNDRTcAL ,', -Lg( o{)-+.

Pop\

op) p-^ o9- oz-

spHERrcAL v,^ a (^) =--L-lu(u::"') -l?'iu. .:{^

Lary--g('l)la"

rsingl a0 A )

'

rlsind d/ dr )

r{a(,n,1 afl. ).

r[ 0r A0)'

LAPLACIAN

spFrERrcAL o,o (^) =Ig(,'91)-f -1[.r9] *^ .]--!

,' 0r\ dr (^) ) ,'^ sin9^ dd^ A0^ ) r'sin"^0 0Q'

S

Yli

gS| :

Y""tt |rylre*1tig-(W

o:)

{ (^) Candidates are required to give^ their^ answers^

in their ouryt^ words^ as^

far as practicable'

/ (^) Auempt 4ll questions"

{ (^) Thefigures in the margin indicate^ Full^

Matr*s'

t

TreOresent a^ vectorard^

i.uu..rp, anci i,,r,"aprdenotes a unit vector

along the^ direction

gru"i ty the subsript.

Assume suitable data^ if^

necessary.

.*-: pelirr.

a vector field. A field^ vector is given

by an expression

i=#(""-vi,*'i.),transformthisvectorincylindricalcoordinate

system at^ point^

Given the flux^ density^ fr =12ccs0lr';a.+(sin0/13)au

Clm2,evaluate both^ sides^

of the

1r^ (^) , It

divergence theorem^ forthe^ region^

defrned by I^ <^ r <2.^

<0 <-,0

(Region 2) has lrr

= i0. if there is a uniform^ magnetic^ freid^

i=S{+e{+ 7i,Al^in

region l,find Band Hinregion2. [2+3+3]

  1. Find the amplitude bf the displacement current density^ in^

a metallic conductor at 60 Hz, if

)+

€=€qrp=p0,6=5.8x107S/m, and^

j

=sin(37?t (^) -117.12\a*MA/m2- t5]

ll+sl

Is+3]

?

t dD1-, dDy , dD V.U=--a=:t;

Cartesian:

Cylindrical:

Spherical:

Cylindrical:

Spherical:

0x 0Y 0z vfi-1a(PDpr+1999+ry Y'v-p aP (^) Pa oz -R td(rzD , t altT-9De)- 1 dDO V. D^ = A a, -;trs- ao- - i"o aO w= T,q;# T" w= fri#6##ao Laplacian Gradient

Cartesian:

Curl v,v=#+#+# cyrindricar: vzv =;*(r#) .if"+#

Spherical:

YzY

iV#) . #(sino#) .

Cartesian:

v xE^

  • (^) W

-T)a

  • (^) (*

*)d

  • (^) (* -*)a v x n = 1;ffi

#)

  • (^) (# -?) {

;(ry

#)a v x^ n^ == ;k(ry

H)d

iffiH

@)a

i(ry-')'; s ** " 22 TzuBHUVAN UNIVERSITY

INSTITUTE OF^ ENGINEERING

  1. Express^ the uniform

vector components. Examinatio n Control Division i.t:gry j-.PE]:-!!x:IJf i (^) :' M"'k' j* 2072 chaitr"^ 'if:lgr!--ini{-- (^) ir'g'---._j 3 }

. iflf1-ili{-- (^) ir'1r'---..i

3 hrs'- ---:--- : ------_j:ryr;t r"--*;eps"cle1telp"$ ----':- r' carrdidates are required to give their answers in^ their own rn'ords as^ iar^ as^ practicable' { (^) Anempt Att questions' / (^) Th"

iTur"s

in the margin indicate Full-Mstk' / (^) Neieisary tables are attached^ herewith' { /r"prurent

a rectorarid lo,0, ond

io,o.*p, denotes a^ unit vector along the^ direction given by the subscriPt. / Assume suitable data if necessary' freld i=sa. in^ (a)^ cylindrical^ components

(b) spherical

[2+3]

A .+- Derive the expression^ for the^ electric freld intensity due^ to^ an^ infrnitely long line^ charge with uniform "t -g" density p,^ by^ using Gauss's law.^

A uniform line charge density^

of 20 nClmis located^

at y (^) =3 and z=5^ ' Find^ E at P(5'6'1) [4+4] Derive an expression^

to calculate the potential^

due to a^ dipole^ in^ terms of the dipole

/-r++++ moment (^) f ol o dipole for^ which^ p=3a*-5a'+10a"nC'm

is located at^ the point

/

[4+4] (1,2,-4). Find E at^ P. Assuming that the potential v^ in^ the^ cylindrical coordinate system^

is function of^ p^ only,

solve the Lapplace's equution and derive the^ expression^

for the capacitance^

of coaxial capacitor of iengtn^ f.^ using the

same solution^ of^ V. Assume the inner conductor^ of radiUs ;;;;t"ttt"i iir trt t"ip to the conductor of radius b'^ t6l

  1. State and^ derive^

expression for stoke's theorem. Evaluate

the^ closed^ line integral of^ H

from

(5,4,i)to Pr(5,6'1)to Pr(0,6,1)to Po(0,4,1)to P,^ using straight^ line segments' if

H = 0.1y3^ a,+0-4xa.Alm^ '

  1. Define scalar magnetic

potential^ and show^

that it satisfies the Laplace's

[1+3+4] equation. Given the vector magnetic^ potential i=-(Ot t+)i,WAtm,^ calculate the total^ magrretic flux crossingtle surface^ 4:n/Z'