Electromagnetic Induction | AC Generator (Alternator) | A-level Physics

This video discusses the AC (alternating current) generator or alternator. With the aid of a PhET simulation (see below), we explore the factors that determine the oscillating induced emf that develops in a coil when a bar magnet rotates. We discuss the derivation of the induced emf formula using Faraday's law of EM induction, and explain key aspects about the emf vs time graph (and its relationship to the flux linkage vs time graph). At the end, we touch on Lenz's law and pose a question for you to answer.

We are grateful to PhET for the simulation used in the video:

PhET Interactive Simulations
University of Colorado Boulder

[ForestLearn]

Answer to question posed at 8:59 (please try to figure it out yourself before taking a look!):


'The coil/loop tries to *oppose* any *changes* in magnetic flux (linkage).'


As the north pole of the rotating magnet moves away from the coil, the coil tries to oppose the changing flux linkage by developing a magnetic South pole on the left side – this thus attracts the rotating magnet. Viewing the coil 'head on' from the left, the conventional current would be flowing clockwiSe.

And so on.

[lamisazamzam]

I would love to know why the current changes direction...

[athulakulasinghe]

Decrease the rate of change of flux by increasing the induced emf

[Insta_Feed]

Would you consider making a video on type 3 as i think thats the type that comes in q most of the time ?