Answer
See answers.
Work Step by Step
a. Large mutual inductance occurs when the current passing through one coil creates a large magnetic flux through the other, and vice versa. With two flat circular coils of wire, to maximize mutual inductance, place them face-to-face, with minimal separation. Nearly all of the magnetic field lines from one coil pass through the other coil.
b. See the discussion in part A. To minimize the mutual inductance of two flat circular coils while keeping them close to each other, align them with their circular faces at right angles. This minimizes the magnetic field lines from one coil that pass through the other coil.
