A coaxial cable consists of a thin inner conductor fixed along the axis of a hollow outer conductor. The two conductor carry equal currents in opposite directions. Let `B_1 and B_2` be the magnetic fields in the region between the conductors and outside the conductor, respectively. Then,

Options

A. `B_1 ne 0 , B_2 ne 0`
B. `B_1 = 0 , B_2 = 0`
C. `B_1 ne 0 , B_2 = 0`
D. `B_1 = 0 , B_2 ne 0`

Answer

C

Explanation

Apply Ampere.s circular law to the coaxial circular loops `L_1 and L_2` The magnetic field is `B_1` at all points on `L_1 and B_2` at all points of `L_2 sumI ne 0` for `L_1 and 0` for `L_2`
Hence , `B_1 ne 0 ` but `B_2 = 0 `
[As `oint vecB.dhati=mu_0sumI`]