# I Induced Magnetic Moment (vector) vs. Induced EMF (scalar)

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1. Nov 20, 2016

### particlezoo

When I induce magnetic flux through a closed loop, I should expect the lines of flux produced by current in that loop to oppose the change of flux through that loop. But what happens when that loop, say a rectangular loop, is curved into the shape of the letter J (like a candy cane) and my flux is mainly cutting through the short end of the J? Would it then be possible for the induced magnetic moment to actually amplify the change of the magnetic moment? How does that not violate Lenz's law?

2. Nov 20, 2016

### Simon Bridge

Um what? Have you tried doing the maths on that?
Anyway - I think you want to know about self-induction.

Unless you are asking about what happens when the changing magnetic flux only passes through part of the loop??

3. Nov 20, 2016

### particlezoo

Yes.

I am asking what happens when the external magnetic field lines pass only through one end of the loop.

In this case, it is a rectangular loop curved into the shape of the letter "J", where the flux crosses through the end of the loop at the smaller end of the "J".

The external magnetic field in this scenario is strongest near this short end of the "J" and weakens with distance. So in this example, the external magnetic field may be produced by a small point magnetic dipole near the short end of the "J" which generates EMF by virtue of rotation and/or translation relative to the fixed closed loop.