Final answer:
When a coil of wire is quickly disconnected or a magnet is moved in and out of the coil, it causes electrons to flow. Slowly inserting a magnet into the coil results in rapid needle movement on the galvanometer.
Step-by-step explanation:
The subject of this question is Physics.
When a coil of wire is quickly disconnected from a galvanometer, it causes electrons to flow. This is because a changing magnetic field induces an electric current in the wire, as described by Faraday's law of electromagnetic induction.
Moving a magnet in and out of the coil also causes electrons to flow. As the magnet moves, the magnetic field through the coil changes, which again induces an electric current.
When a magnet is slowly inserted into the coil, it produces rapid needle movement on the galvanometer. This is because the changing magnetic field induces a stronger electric current.
Learn more about Electromagnetic induction