White the difference between potential difference and emf.

Potential difference is the work done by the electric force on unit positive charge to move it through a distance l from point A to B is called potential difference between these two points. V = W/q = f_el/q

Where V = potential difference;

W = work done by the electric force

q = free charge

l = distance

f_e = force exerted by the electric field

The work done by the chemical force to move unit positive charge from negative terminal to positive terminal of the battery is called electromotive force.

EMF = W/q = Fd/q