Question

A short bar magnet allowed to fall along the axis of horizontal metallic ring. Starting from rest, the distance falls by the magnet in one second may be:

• A. $4.0m$
• B. $5.0m$
• C. $6.0m$
• D. $7.0m$

Answer 1

The correct option is B $5.0m$

When a short bar magnet allowed to fall along the axis of horizontal metallic ring, then it will fall under the influence of gravity.

$\because s=ut+\frac{1}{2}g{t}^2$

$here,u=0andt=1\sec$

$s=\frac{1}{2}\times 10\times 1$

$=5m$

The distance falls by the magnet in one second is less than $5m$ because when the magnet falls freely through the ring, flux increases and a field is induced whose direction is opposite to that of bar magnet. the magnet experiences a repulsion and hence acceleration of magnet becomes less than g.