A horizontal rod (oriented in the east-west directionis moved northward at constant velocity through a magnetic field that points straight down. Make a statement concerning the potential induced across the rod."

Faraday's law: A changing magnetic field induces an emf.

Lenz's law:  current produced by an induced emf moves in a direction so that its magnetic field opposes the original change in flux.

The three ways that an emf can be induced in a loop of wire.
1. by changing the magnetic field
2. by changing the area of the loop in the field
3. by changing the loop's orientation with respect to the field