electric  potential Consider a point charge Q and two points A and  B  as shown in the fig.e2. The work required to move a unit charge from B to A is,

W_BA = - ò E(r).ds = -ò E(r)dr

which  is  independent  of  the path (see fig.e2). Therefore the work done in bringing a unit positive charge from infinity to any point r is

W_r= - ò E.ds = V(r)

which is unique for the point r. The function V(r) is called the potential function. For a point charge Q,

V(r) = [1/(4 p e ₀)] [Q/ r]