The direction of induced e.m.f. can be found by

Answer: Option B

The direction of induced electromotive force (e.m.f.) can be found by Lenz's law.

Lenz's law states that the direction of the induced electromotive force (e.m.f.) in a circuit is such that it opposes the change in magnetic flux that causes it. In other words, when there is a change in magnetic flux passing through a coil or a conductor, an e.m.f. is induced in the conductor in a direction that produces a magnetic field opposing the change in the original magnetic field.

This law helps to understand the direction of the induced current and the polarity of the induced voltage when a magnetic field is changing in a conductor, coil, or any closed-loop circuit. It is a fundamental principle in electromagnetic induction and is used to analyze and predict the behavior of inductors and transformers in electrical and electronic circuits.