0
$\begingroup$

we know that an open surface integral of magnetic field bounded by a closed contour gives the magnetic flux. And rate of change of the magnetic field gives the Electromotive force. Now, if we have a solenoid ,which we can bound a open surface, and a magnet, we could induce a current by changing the magnetic flux. But ,say, we have a filled disk (not hollow) (or any other solid object) and do the same thing, we know there would be an induced electromotive force. But the problem here is, we cannot have an open surface which bounds the disk, disk is a simply 3D object and therefore it can be bound only via closed surfaces. The problem is, closed surface integral of the magnetic field is always zero, therefore rate of change of the magnetic flux is also zero. In the end we shouldn't induce any Emf on the object But we know we can, how so?

$\endgroup$

1 Answer 1

0
$\begingroup$

The surface you integrate over to calculate magnetic flux is mathematical; it doesn't need to line up with anything physical. You can still find the magnetic flux through an open surface associated with the disk, for example, a cross-sectional area.

$\endgroup$
1
  • $\begingroup$ suppose it is a solenoid with tight rounds so that it almost looks like a 3-D disk, then when u calculate the magnetic flux, according to ur explanation, will u just assosicate one circle to it? $\endgroup$
    – ozgun can
    Aug 13, 2021 at 17:40

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.