Use the expression for the magnetic field of a loop to find an expression for the magnitude of the magnetic field at point P, a distance a/2 from the center of each coil Note that there is a total of 2N turns in the two coils.

Explanation:

The magnitude of the magnetic field at a point P, a distance a/2 from the center of the each coil can be determined as follows;

Let the magnitude be M;

Note that there is a total of 2N turns in the two coils.

So, we have:

where x = distance (d) which is given as a/2; we have:

so easy. just google the electromagnetic waves and it’ll pop up.