Two identical current carrying coaxial loops, carry current I in an opposite sense. A simple amperian loop passes through both of them once. Calling the loop as C,

Options

A. `ointB.dl=m mu_(0)I`
B. The value of `ointB.dl=overset(-)(+)2mu_(0)I` is independent of sense of C.
C. There may be z point of C where, B and dl are perpendicular
D. B vanishes everywhere on C.

Answer

B, C

Explanation

Applying the ampere's circuital law, we have
`oint=B.dl=mu_(0)(I-I)=0` (because current is in opposite sence).
Also, there may be a point on C where B and dl are perpendicular and hence,
`underset(c)ointB.dl=0`.