20.5.4—Experiments that demonstrate: • that a changing magnetic flux can induce an

When magnetic flux linkage changes, an emf is induced; the induced effect opposes the change according to Lenz’s law.

Change field, area, orientation or motion to change linkage. A complete conducting path is needed for induced current, but emf can exist with an open circuit.

Moving a magnet into a coil gives a transient current whose direction reverses when the magnet is withdrawn.

A static magnetic field alone does not induce emf; it must produce changing flux linkage through the circuit.