Magnetic Forces

Motors and auroras

An interactive lesson with 6 steps, about 5 minutes: you predict, drag and solve, with instant feedback on every answer. It runs in your browser and needs JavaScript.

What you’ll learn

• A moving charge feels $F = qvB$, sideways to both its motion and the field.
• Charged particles circle in a magnetic field, with radius $r = mv/(qB)$.
• A current-carrying wire feels $F = BIL$. That's how motors work.

Steps

1. Sideways push
2. Circling charges
3. Northern lights
4. Forces on wires: motors
5. An electron’s circle
6. Force on a wire