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force is an i)a"inary strai"ht or c(r*e! 'ath alon" hich a (nit
'ositi*e char"e ten!s to
)o*e in an electric fiel!.
1#. STATE THE PROPERTIES O$ ELECTRIC LI%ES O$ $ORCE. 0i3 Lines
of force
start fro) 'ositi*e char"e an! ter)inate at ne"ati*e char"e.
0ii3 Lines of force ne*er
intersect. 0iii3 The tan"ent to a line of force at any 'oint
"i*es the !irection of the electric
fiel! 0E3 at that 'oint. 0i*3 The n()ber of lines 'er (nit area,
thro("h a 'lane at ri"htan"les to the lines, is 'ro'ortional to the
)a"nit(!e of E. This )eans that, here the lines
of force are close to"ether, E is lar"e an! here they are far
a'art, E is s)all. 0*3 Each
(nit 'ositi*e char"e "i*es rise to 1 o lines of force in free
s'ace. Hence n()ber of linesof force ori"inatin" fro) a 'oint
char"e @ is % @ in free s'ace.
13. DEFINE ELECTRIC DIPOLE.GIVE EXAMPLES.
To e@(al an! o''osite char"es se'arate! by a *ery s)all !istance
constit(te an electric!i'ole. Water, a))onia, carbon!io2i!e an!
chlorofor) )olec(les are so)e e2a)'les of
'er)anent electric !i'oles 14.5E$I%E 5IPOLE 8O8E%T.WRITE
EPRESSIO%,%IT. The )a"nit(!e of the !i'ole )o)ent is "i*en by
the 'ro!(ct of the)a"nit(!e of the one of the char"es an! the
!istance beteen the). Electric !i'ole
)o)ent, ' @#! or #@!. It is a *ector @(antity an! acts fro) M@
to @. The (nit of !i'ole
)o)ent is C ). 1.5E$I%E TOR:E EPERIE%CE5 9& ELECTRIC 5IPOLE?
The)a"nit(!e of tor@(e is, N One of the forces 2 'er'en!ic(lar
!istance beteen the forces
$ 2 #! sin @E 2 #! sin 'E sin 0@ = #! P3 %ote ; If the !i'ole is
'lace! in a
non(nifor) electric fiel! at an an"le , in a!!ition to a tor@(e,
it also e2'eriences aforce.
16. DEFINE ELECTRIC POTENTIAL ENERGY OF AN ELECTRIC DIPOLE
Electric 'otential ener"y of an electric !i'ole in an
electrostatic fiel! is the or+ !one inrotatin" the !i'ole to the
!esire! 'osition in the fiel!.
1F.5ESCRI9E THE WORI%- O$ 8ICROWA7E O7E%. It is (se! to coo+ the
foo!
in a short ti)e. When the o*en is o'erate!, the )icroa*es are
"enerate!, hich in t(rn'ro!(ce a non (nifor) oscillatin" electric
fiel!. The ater )olec(les in the foo! hich
are the electric !i'oles are e2cite! by an oscillatin" tor@(e.
Hence fe bon!s in the ater
)olec(les are bro+en, an! heat ener"y is 'ro!(ce!. This is (se!
to coo+ foo!.
The 'otential !ifference beteen to 'oints in an electric fiel!
is !efine! as the a)o(nt
of or+ !one in )o*in" a (nit 'ositi*e char"e fro) one 'oint to
the other a"ainst the
electric force. The (nit of 'otential !ifference is *olt
18. DEFINE POTENTIAL DIFFERENCE.
The 'otential !ifference beteen to 'oints is 1 *olt if 1 /o(le
of or+ is !one in )o*in"1 Co(lo)b of char"e fro) one 'oint to
another a"ainst the electric force.
1!. DEFINE THE UNIT OF POTENTIAL DIFFERENCE.
"#. DEFINE ELECTRIC POTENTIAL.
The electric 'otential in an electric fiel! at a 'oint is
!efine! as the a)o(nt of or+ !one
in )o*in" a (nit 'ositi*e char"e fro) infinity to that 'oint
a"ainst the electric forces.
#1.5E$I%E ELECTRIC POTE%TIAL E%ER-&. The electric 'otential
ener"y of to
'oint char"es is e@(al to the or+ !one to asse)ble the char"es
or or+!one in brin"in"
each char"e or or+ !one in brin"in" a char"e fro) infinite
!istance
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##. 5E$I%E E:IPOTE%TIAL SR$ACE, If all the 'oints of a s(rface
are at the sa)e
electric 'otential,then the s(rface is calle! an e@(i'otential
s(rface .If the char"e is to be
)o*e! beteen any to 'oints on an e@(i'otential s(rface thro("h
any 'ath, the or+!one is Kero.
#B.5E$I%E ELECTRIC $L The electric fl(2 is !efine! as the total
n()ber of electric
lines of force, crossin" thro("h the "i*en area. E . !s#4.5E$I%E
-ASSGS LAW -a(ssGs la states that the total fl(2 of the electric
fiel! E
o*er any close! s(rface is e@(al to1Jo ti)es the net char"e
enclose! by the s(rface.
@Jo#.5E$I%E ELECTROSTATIC SHEIL5I%- Electrostatic sheil!in" is
the 'rocess of
isolatin" a certain re"ion of s'ace fro) e2ternal fiel!. It is
base! on the fact that electric
fiel! insi!e a con!(ctor is Kero. #
