The solution at revision #18612 of , by Luisito. This is not the current version.

Statement

11.2.6. [Insert the problem statement]

Solution

Supposing a ring of radius whose center is in the coil axis:

but (where is the vector in direction of induced electric current on the ring that follows the lenght of the ring)
(1)
Moreover,
, (2)
Putting (2) into (1) and taking in account that


The EFM for the coil is given by,ç
(3)
From (2) and (3),

Calculating:

Answer

[Insert a concise answer or boxed result]