Question

A long straight cylindrical shell has an inner radius R_i and an outer radius R₀. It carries a current I, uniformly distributed over its cross section. A wire is parallel to the cylinder axis, in the hollow region (r < R_i). The magnetic field is zero everywhere outside the shell (r > R₀).

We conclude that the wire: 

A) is on the cylinder axis and carries current I in the same direction as the current in the shell 

B) may be anywhere in the hollow region but must be carrying current I in the direction opposite to that of the current in the shell 

C) may be anywhere in the hollow region but must be carrying current I in the same direction as the current in the shell 

D) is on the cylinder axis and carries current I in the direction opposite to that of the current in the shell 

E) does not carry any current.

Answer 1

Correct option is D

Explanation is given below

Hope this helps...