Ampere's law wire problem

[ZeroVersion]

Hellow every one I have small Q but I stuck on it

there is pic attached


hope to be intersting and clear to you

1. The problem statement, all variables and given/known data
rank the loops accoroding to the current enclosed greatest first
2. Relevant equations

we have three eqn's
B = u "node" I encِْْْْ
B = u"node" i / 2 pi r outside the wire
B = (u"node" i / 2 pi R2 ) r inside the wire
3. The attempt at a solution


I knew the solotion but I do not know how did they get it

the soloution is d and c tie then b then a

[Doc Al]

Hint: Treat the current density as uniform across the wire.

[ZeroVersion]

thank you very much Doc al it is as what you mentioned related to the current density for c and d the current is the same whereas in b smaller and a is even smaller than b



Sometimes we think in very difficult method when we can solve it in easier way


Thank you again and regards