A bar magnet falls from rest under gravity through the centre of a horizontal ring of conducting wire as shown in figure. Which of the following graph best represents the speed ((v) v s ). time (t) graph of the bar magnet?

Step-by-step solution

- A bar magnet falling through a conducting ring induces eddy currents (Lenz's law). - These currents oppose the motion, so the speed does not increase uniformly. - When the magnet is approaching the ring, induced current opposes motion ( ) speed rises slower. - As the magnet passes the center of the ring, flux change is momentarily zero ( ) no opposing force ( ) speed increases. - As the rear end leaves the ring, induced current again opposes motion ( ) temporary reduction in acceleration (or speed dips). - After