Figure shows cross section of two large parallel metal sheets carrying electric currents along their surface. The current in each sheet is `10//pi A//m` along the width, Consider two points A and B, as shown in the figure with their positions.

Options

A. Megnetic field at A is `4mu T` along x-direction.
B. Magnetic field at A is `4 mu T` along negative x-direction.
C. Magentic field at B is zero.
D. Magnetic field at B is `2 mu T` along x-direction.

Answer

A, C

Explanation

Field due to each plate `=1/2 (mu_0)K=2(mu)K=2(mu)T`
At A, field add up, being in the same direction whereas at B, fields cancle out due to opposite directions.