Analog Electronics MCQ Questions & Answers | ECE

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.

In an iron cored coil, the presence of the iron core significantly increases the inductance due to the higher magnetic permeability of iron compared to air.

When the iron core is removed, the coil becomes an air cored coil, which has much lower magnetic permeability.

As a result, the inductance of the coil will decrease.

A crack in the magnetic path of an inductor creates a gap in the core, disrupting the continuous magnetic flux.

This disruption increases the reluctance of the magnetic circuit, which reduces the overall inductance of the inductor.

As a result, the inductance will be reduced rather than remaining unchanged or increasing.