# Example: Ampere's Law

From Class Wiki

### 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

The mean path length is

The mean path length encloses the current i N-times.From Eq. 5-1

One can assume a uniform H_{m} throughout the cross-section of the toroid because the width is smaller than the mean radius.

### Author

Tyler Anderson