MHTCET 22 Apr 2025 Shift 1 Paper

Concept:The falling magnet induces a current in the copper ring, and Lenz's law opposes the motion causing the induction.Explanation:When the bar magnet falls through the ring, the magnetic flux linked with the ring changes continuously.By Lenz's law, the induced current in the ring opposes the change in flux.This opposition appears as a magnetic force that acts upward on the falling magnet.Thus, while passing through the ring, the magnet experiences two forces: its weight $mg$ downward and the magnetic drag force $F$ upward.So the net downward force becomes $mg - F$, giving an acceleration $a = g - \frac{F}{m}$.Since $\frac{F}{m} > 0$, we get $a < g$.Therefore, the magnet falls with an acceleration less than the acceleration due to gravity.The exact value depends on the induced current, but qualitatively the acceleration is always less than $g$ during its passage through the ring.Answer:The acceleration of the falling magnet is less than acceleration due to gravity.Hence, the correct option is B.