- #1

- 3

- 0

Is anybody able to explain why it is the cross sectional area of the coil?

I understand it in terms of a length of wire as the cross section of that is cutting field lines but in terms of a coil I'm confused as you have the whole central area of the coil which is empty and therefore not cutting field lines so why is the cross sectional area of the coil used and not just the area of the coil cutting the field lines?