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 induction at a point due to a current through a long straight wire depends only on the distance from x-axis. Points A and C are at distance of 1 unit each from x-axis. Points B and D are at distance `sqrt2` unit each from x-axis.