IIT JEE , AIEEE Forum - Physics , Electricity

ultimator

What is the electric potential at pt P due to this infinite line charge ?

sagarvaze

Re:Electric Potential

ultimator

Nope, that's not right.

ultimator

Common mistake is to use electric field formula n find the potential.

In fact, the potential is not defined at all.

Wondering , why ???

Well, i'll need some1 to ask me for the answer ! Lol.....

The soln is very simple actually, nothin is difficult for goiitians.

ananth_patri

y?????????well

ultimator

Because, u need to consider the potential to be zero at point, which we normally take it to be at infinity.

But, potential at infinity cant be zero in this case , as the line charge extends upto infinity !

Nice answer , right ? Come on , rate me !

ananth_patri

so how come potential is not defined???

ultimator

Because u cant define any pt to be at zero potential !

So, potential at other points is not defined !'

Let me rephrase my answer.

In this case, v cant take reference pt for pot at infinity as wire itself is of infinite dimension n hence we cant define absolute potential due to this infinite charged wire.

ananth_patri

well may be u r rite.....nice.....

me_living4u

see ........ easy if we follow basics...

dV = EdR

rit

so Vb - Va = int. of Edr frm a to b

E = lambda / 2 pie epsilon not r

integrating Edr=

we hve Vb - Va= [lambda/2 pie epsilon not] ln Rb - ln Ra = [lambda/2 pie epsilon not] ln [Rb/Ra]

so this is pot between any two points ryt...

a and b

so if we take inf as b and its pot to b zero as convention thn we have

so Vb = Va + [lambda/2 pie epsilon not] ln [Rb/Ra]

whre Va is pot. at any reference point a.

so u can take any point as refernce point and decide potential diff accordingly...

conventionally Vinf = 0.... now if we take that into acc. thn Vb is undefined .... so we must take a sparate reference point .... and not infinity

and thus we can calc. pot at any point

cheers!!!!!!!!!

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