Time period for a magnet is T. If it is divided in four equal parts along its axis and perpendicular to its axis as shown, then time period for each part will be

When magnet of length l is cut into four equal parts, thenm'=m2 and l'=l2;    ∴M'=m2 x l2=ml4=M4New moment of inertiaI'=w'l'212=w4.l2212=116.wl212Here w is the mass of magnet.∴I'=116ITime period of each Part, T'=2πI'M'BH=2πI/16M/4BH=2πI4MBH=T2