Question

who has gives theory of emf

Answer 1

Mickal Farday has given theory of emf.

Hope it will help you.. : )

Answer 2

Electromotive force, abbreviated emf(denoted {\displaystyle {\mathcal {E}}} and measured in volts),[1] is the electrical intensity or "pressure" developed by a source of electrical energy such as a batteryor generator.[2] A device that converts other forms of energy into electrical energy (a "transducer") provides an emf as its output.[3](The word "force" in this case is not used to mean mechanical force, as may be measured in pounds or newtons.)

In electromagnetic induction, emf can be defined around a closed loop of conductor as the electromagnetic work that would be done on an electric charge (an electron in this instance) if it travels once around the loop.[4]For a time-varying magnetic flux linking a loop, the electric potential scalar field is not defined due to a circulating electric vector field, but an emf nevertheless does work that can be measured as a virtual electric potential around the loop.[5] (While electrical charges travel around the loop, their energy is typically converted into thermal energy due to the resistance of the conductor comprising the loop