# Area perpendicular to a magnetic field from Faradays Law

1. Dec 25, 2012

### jearls74

Hello Everyone,

I have a question concerning the "Area perpendicular to the magnetic field".

If the field was produced by a permanent magnet, would the "Area perpendicular to

the magnetic field" be the same size as the Area of the permanent magnet?

2. Dec 25, 2012

### Staff: Mentor

The area can be anything you want. It just depends on what you are trying to find. Can you provide more context to your question?

3. Dec 25, 2012

### jearls74

When calculating voltage for an axial flux generator with a permanent magnet rotor,

would the "Area perpendicular to the magnetic field" be the Area that the wire in the stator

occupies, or would the "Area perpendicular to the magnetic field" be the same size as the

Area of the permanent magnet? I believe the " Area perpendicular to the magnetic field" is

is Area of the permanent magnet that the field is coming from and not the Area of the stator

that the wire occupies but i need someone that knows more about Faradays Law to tell me

if im right or not?

4. Dec 26, 2012

### dlgoff

5. Dec 26, 2012

### jim hardy

Nice job Don !!! Great link, and scholarly....

The voltage is determined by the magnetic flux enclosed by your turns.... Well,,, Actually by rate of change of that flux....
Probably there's several different ways to calculate that.

@ original poster:
Brush up on your magnetic units.
One weber per second will cause one volt in one turn whatever its area. You'll have to adapt that to whatever geometry and units you are given.

old jim