Work done by a source to maintain current in an electrical circuit is called an electric current.
Electric power can be defined as rate of doing electrical work.
A cell is a electrical device which provides the necessary potential difference in an electrical circuit to maintain the flow of current.
Emf (electro motive force)
Emf of the may be defined as the potential difference between its terminal when no current is drawn from the cell.
Magnetic flux through any surface is define as a total number of magnetic field line passes through the surface.
Whenever there is a change in magnetic flux linked with a coil an emf induce in the coil this emf is as long as there is change in magnetic flux.
The magnitude of induce emf is directly proportional to the rate of change of magnetic flux linked with a coil.