Question

difference between e.m.f and p.d.

Answer 1

Electromotive force (emf) refers to the ability of a circuit to do work on electrically charged particles. Since this work is done by the electromagnetic force, the force exerted on the charge (and hence the total work) will be proportional to the magnitude of the charge. The proportionality constant is what we call the emf. Thus, the total work done is the product of the emf and the particle's charge.

When there is an electric potential difference between two points on a circuit, an emf results, because electric field lines point from high potential to low potential, and the electrostatic force can do work on charges. When there are only electrostatic forces, the emf is equivalent in magnitude to the electric potential difference, because the electric potential difference is defined to be the work done in moving a unit test charge from one point to another.

Answer 2

Basically both electronics force and potential difference are same but they are diffrent when internal resistance present in cell.