The dimension of electromotive force are?

Calculate the e.m.f of the cell in the above circuit if its internal resistance is negligible

The correct expression for the potential at a point distance r from a charge q in an electric field is?

What is the effect of using split-rings in a simple d.c motor?

What is the electric potential energy between two protons each of charge q and at a distance of r apart? (Permittivity of free space = εo)