- #1

thebosonbreaker

- 32

- 5

I have been studying electromagnetic induction and have looked at the laws of Faraday and Lenz.

Faraday's law makes perfect sense to me, but I can't seem to grasp Lenz's law. I have read about it and watched many yt videos, and the idea seems simple. But actually using it to predict e.g. the direction of induced emf, I am having some trouble with.

Consider the following diagram. It shows a conductor being moved downwards through the poles of two magnets.

The flux through the conductor is changing, so an emf is induced. Lenz's law tells us that: 'The direction of the induced emf is such as to oppose the change that caused it.'

As I understand it, this means that the current induced in the conductor will flow in a direction such that it creates a magnetic field which is opposing the CHANGE IN the external magnetic field (going L>R in the diagram between the magnets). This counteracts the downwards motion of the conductor. This makes sense.

But how do I actually work out the direction of this current? I don't understand how exactly the external field is "changing" as the conductor moves through it.

Could somebody please clarify this and talk through how they would work it out.

Many thanks in advance.

Faraday's law makes perfect sense to me, but I can't seem to grasp Lenz's law. I have read about it and watched many yt videos, and the idea seems simple. But actually using it to predict e.g. the direction of induced emf, I am having some trouble with.

Consider the following diagram. It shows a conductor being moved downwards through the poles of two magnets.

The flux through the conductor is changing, so an emf is induced. Lenz's law tells us that: 'The direction of the induced emf is such as to oppose the change that caused it.'

As I understand it, this means that the current induced in the conductor will flow in a direction such that it creates a magnetic field which is opposing the CHANGE IN the external magnetic field (going L>R in the diagram between the magnets). This counteracts the downwards motion of the conductor. This makes sense.

But how do I actually work out the direction of this current? I don't understand how exactly the external field is "changing" as the conductor moves through it.

Could somebody please clarify this and talk through how they would work it out.

Many thanks in advance.