A long straight wire carries the current along +ve x-direction. Consider four points in space `A(0,1,0), B(0,1,1), C(1,0,1), and D(1,1,1)`. Which of the pairs will have the same magnitude of magnetic field?

Options

A. `A` and `B`
B. `A` and `C`
C. `B` and `C`
D. `B` and `D`

Answer

B,D

Explanation

The magnitude of the magnetic field depends only on the distance from the `x-` axis. Points A and C are at distance of 1 unit each from the `x-` axis. Point B and D are at distances of `sqrt(2)` unit each from the `x-` axis.