The electric potential V is the amount of work/energy needed per unit of electric charge to move the charge from a reference point to a specific point.

Electric potential

For example, if we wanted to move a positive charge from point A to point B in the electric field shown in the figure, we would have to do work on the charge, since the electric field would push against us.

ΔV = W / q
Measured in joules/coulomb or volts

Electric potential

If we place the charge q at point B and let it go, it will 'fall' toward point A.
We say that positive charges naturaly want to move from a point of high potential (B) to one of low potential (A).
We can write the electric potential due to a source charge Q at a distance r from the source charge:

V = k Q / r

Electric potential

There exists an electrical potential energy between two charges q₁ and q₂ which is equal to the work needed to bring the two charges from an infinite distance apart to a separation distance r:
U_E = k.q_1.q₂ / r
U_E = W = q.V
q is the charge being moved in the electric field of the other charge.

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​Electric potential energy

​Is a region of space where the strength and direction of an electric field are the same at every point.
E = V / d
Unit = volts/meter

Uniform electric field