When the magnet is pushed in and pushed out then there is change in magnetic flux. According to faraday's law of electromagnetic induction, current is induced and galvanometer deflects.
Faraday's Law of Electromagnetic induction is the process in which an electromotive force (emf) is induced in a closed circuit due to changes in the magnetic field around the circuit.Electromagnetic Induction or Induction is a process in which a conductor is put in a particular position and magnetic field keeps varying or magnetic field is stationary and a conductor is moving. This produces a Voltage or EMF (Electromotive Force) across the electrical conductor.
A current can be induced in a conducting loop if it is exposed to a changing magnetic field. In other words, if the applied magnetic field is increasing, the current in the wire will flow in such a way that the magnetic field that it generates around the wire will decrease the applied magnetic field.Electromagnets- objects that are magnetic only when electric current is flowing. induced magnetism- magnetism that is present only when an electric current is flowing.
Most textbooks on electricity and magnetism distinguish the magnetic field H and the magnetic induction B. Yet, in practice physicists and chemists almost always call B the magnetic field, which is because the term "induction" suggests an induced magnetic moment.