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

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