1. Electric Potential

Electric potential of a point r meter from a charge:

$V=k{\displaystyle \frac{Q}{r}}$

2. Electric Potential Difference

Electric potential difference between 2 points:

$\mathrm{\Delta }V=V_2-V_1$

$\mathrm{\Delta }V=k{\displaystyle \frac{Q}{r_2}}-k{\displaystyle \frac{Q}{r_2}}$

$\mathrm{\Delta }V=kQ({\displaystyle \frac{1}{r_2}}-{\displaystyle \frac{1}{r_1}})$

If two points have different potential, higher potential symbolized with (+) and lower potential with (−).

Between two points which have different potential, electric field will produced.

$\mathrm{\Delta }V=E.d$

2. Electric Potential Energy

electric potential energy between two charges:

A charge can move from one point to another which have different potentials. The work done by the charge is:

$$\begin{array}{rl}W& =\mathrm{\Delta }{E}_p\\ \\ W& =E_{p_2}-E_{p_1}\\ \\ W& =q{V}_2-q{V}_1\\ \\ W& =q(V_2-V_1)\\ \\ W& =q.\mathrm{\Delta }V\end{array}$$