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!!!!!!!!!