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 it. The magnet is then moved towards the coil.
Answer the following question in this context.
The bar magnet is brought close to the coil and then stopped. What happens after it is stopped?
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → None of these
An emf is induced in the coil only while the magnetic flux through it is changing. Once the magnet is at rest, the flux through the coil stays constant.
Option (1) The current remains constant. — Incorrect. With the magnet at rest, no emf is induced. So the current falls to zero. It does not stay at the value it had during the motion.
Option (2) The emf continues to be induced in the coil. — Incorrect. The induced emf equals the rate of change of flux, and this rate is zero once the magnet stops.
Option (3) The galvanometer stays deflected. — Incorrect. The deflection lasts only while the magnet moves; with no current the pointer returns to zero.
Option (4) None of these — Correct. None of the three statements holds. With a constant flux, there is no emf, so there is no current and no deflection.
NCERT (2026-27):
The Experiments of Faraday and Henry – “… When the North-pole of a bar magnet is pushed towards the coil, the pointer in the galvanometer deflects, indicating the presence of electric current in the coil. The deflection lasts as long as the bar magnet is in motion. The galvanometer does not show any deflection when the magnet is held stationary.”