Case: Read the passage and answer the question.
Consider a coil C1 connected to a galvanometer G, as shown. A bar magnet is placed near the coil with its north pole facing the coil and its south pole away from the coil. The magnet is then moved towards the coil.
What is responsible for the generation of current in the coil?
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → Relative motion of the coil and the magnet
Option (1) Deflection of the galvanometer needle — Incorrect. The deflection is an effect of the current. The galvanometer only detects the current that is induced in the coil.
Option (2) Movement of the south pole towards the coil — Incorrect. The pole facing the coil is the north pole. The same current also appears when the magnet is held fixed and the coil is moved towards it, with no pole moving at all.
Option (3) Relative motion of the coil and the magnet — Correct. The galvanometer deflects only while the magnet moves. It shows no deflection when the magnet is held stationary. Moving the coil towards a fixed magnet gives the same effect. The relative motion changes the magnetic flux through the coil, and this induces the current.
NCERT (2026-27):
The Experiments of Faraday and Henry – “… Instead, when the bar magnet is held fixed and the coil C1 is moved towards or away from the magnet, the same effects are observed. It shows that it is the relative motion between the magnet and the coil that is responsible for generation (induction) of electric current in the coil.”