Question

The SI unit of electromotive force is_________.

Answer 1

Hint: The electromotive force is the energy provided by a battery or cell per coulomb of charge passing through it, it is measured in volts $\left( V \right)$. The electromotive force is denoted by an acronym emf.

Complete step by step solution:
A time-varying magnetic field inside the electrical generator creates an electric field via electromagnetic induction, In which between the generator terminals a voltage difference is produced. Due to the electrons flow away from one terminal toward the other charge separation takes place within the generator, until, in the open-circuit case, because of development of an electric field that makes further charge separation impossible.
The electromotive force is countered by the electrical voltage due to charge separation. This voltage can drive a current if a load is attached. The general principle governing the electromotive force in such electrical machines is Faraday's law of induction.

Formula for electromotive force is
 $E\, = \,V\, + \,Ir$
Where,
$V$ is the voltage of the cell
$I$ is the current across the circuit
$r$ is the internal resistance of the cell
$E$ is the electromotive force
 Electromotive force = amount of work done / quantity of charge transferred
So, the unit of emf = Joule/ coulomb
Also, joule/coulomb is equal to volt
The electromotive force symbol is ε.
EMF dimension is given as ${M^1}{L^2}{T^{ - 3}}{I^{ - 1}}$

$\therefore$ The unit of emf is $volt$ which is also the unit of potential difference and electric potential.

Note:
Electromotive force is used in the electromagnetic flowmeter which is an application of Faraday’s law. When an inductor produces emf opposite to the incoming power then it is taken as negative as the direction of flow is opposite to the real power.