Answer to Question #316003 in Electricity and Magnetism for redcilli

Question

What happens when a long, straight conductor is moved through a uniform magnetic field at constant velocity? Assume that the conductor moves perpendicular to the field.

Answer 1

An electric field v×B is created perpendicular to both v and B unless v is parallel to B.

$\theta=0°$

Unless the conductor is in the plane of v and B a potential difference is set up along the conductor.

This is how electric generators work. It's called induced EMF.

The potential is maximized if v, B, and the conductor are all mutually perpendicular.

$\theta=90°$

If you complete a circuit through the conductor a current is set up providing v×B isn’t the same all around the circuit: e.g., part of the circuit is outside the field and/or not moving.