Example: Ampere's Law

Problem Statement

Consider a toroid which has N = 50 turns. The toroid has an ID = 10cm and OD = 15cm. For a current i = 5A calculate the field intensity H along the mean path length within the toroid. (this problem is similar to Example 5-1 in the text book)

Solution

The magnetic field intensity H_m is constant along the circular contour because of symmetry. The mean path length is $r_{m}={\frac {1}{2}}*({\frac {OD+ID}{2}})$ The mean path length is $L_{m}=2*\pi *r_{m}=2\pi *6.25$