An electric dipole consists of two charges of equal magnitude and opposite sign saperated by a distance 2 a as shown in figure . The dipole is along the x axis and is centered at the origin

(A) Calculate the electric potential at point P .
(B ) Calculate V at a point far from the dipole .

Explanation

(A) For point P , in figure
`V = k_(e ) sum(q_(i))/(r_(1))= k_( e )((q)/(x-a)-(q)/(x+a))= ( 2 k_(e ) qa)/(x^(2)-a^(2))`
(B) If point P is far from the dipole , such that `x gt gt a`, hen `a^(2)` can be neglected in the term `x^(2) - a^(2)` and V becomes
`V = ( 2 k_(e ) qa)/( x^(2))` ` ( x gt gt a)`