Concept:Electromagnetic induction produces a deflection only when the magnetic flux linked with the coil changes.
Explanation:The galvanometer pointer deflects only when there is relative motion between the magnet and the coil.
Relative motion causes the magnetic flux through the coil to change, inducing an
emf and a current.
Check each statement carefully:
(a) Moving the magnet towards the stationary coil creates relative motion.
The magnetic flux through the coil changes, so the pointer deflects.
Hence, statement (a) is correct.
(b) Moving the magnet away from the stationary coil also creates relative motion.
The flux changes in the opposite direction, so the pointer deflects in the opposite direction.
Hence, statement (b) is correct.
(c) Moving the coil towards the stationary magnet also produces relative motion.
The flux linked with the coil changes, so the pointer deflects.
Hence, statement (c) is correct.
(d) Moving the coil and the magnet together without relative motion keeps the flux linked with the coil constant.
No
emf is induced, so no current flows and the pointer does not deflect.
Hence, statement (d) is wrong.
Answer:Only statement (d) is wrong, so the correct option is D.