Please answer all parts and show your work.

Toroidal magnets are essentially solenoids bent into the shape of a "doughnut". Consider a toroid with a square cross-section of height, h, and inner radius, a, and an outer radius, b. A cut-away view of part of the toroid is shown below. The toroid has a total of N turns of wire and carries a current, I. Using Ampere's law, calculate the magnetic field inside the toroid as a function of r, the radial distance from the center of the toroid (center of the circle). h a