When a strong magnet is passed rapidly through a coil of wire what is true?

The magnetic field lines (the lines of force) around the magnet sweep the windings in the coil. This induces a voltage in the windings (through induction), and the voltage will try to drive current if it can. There is a bit more to this, but the essential elements are that the magentic lines of force cause voltage in the coil because there is relative motion between the field and the coil.