Question

A coaxial cable consists of a thin inner current carrying wire fixed along the axis of a hollow current carrying tube. Let $B_{1}and{B}_2$ be the magnetic fields in the region between the conductors and outside the tube respectively, then:

• A. $B_1\ne 0,B_2\ne 0$, for the conductors carrying equal currents in opposite directions.
• B. $B_1\ne 0,B_2=0$, for the conductors carrying equal currents in opposite directions.
• C. $B_1\ne 0,B_2\ne 0$, for the conductors carrying equal currents in same directions.
• D. $B_1\ne 0,B_2=0$, for the conductors carrying equal currents in same directions.

Answer 1

Answer: (B), (C)

The correct options are
B $B_1\ne 0,B_2=0$, for the conductors carrying equal currents in opposite directions.
C $B_1\ne 0,B_2\ne 0$, for the conductors carrying equal currents in same directions.


By ampere’s law