B Field of a ¥ Solenoid
To calculate the B field of the ¥ solenoid using Ampere's Law, we need to justify the claim that the B field is 0 outside the solenoid.
- To do this, view the ¥ solenoid from the side as 2 ¥ current sheets.
- The fields are in the same direction in the region between the sheets (inside the solenoid) and cancel outside the sheets (outside the solenoid).
- Draw square path of side w: