A thin rectangular magnet suspended freely has a period of oscillation equal to T Now, it is broken into equal halves (each having half of original length) and one piece is made to oscillate freely in the same field. If its period of oscillation is T', then the ratio T'/T is

The moment of inertia of original magnetI=ml212When it is broken in two parts, each part has a mass half and length half. The new moment of inertia I', of each part becomesI′=(m/2)(l/2)212=ml212×18=I8Also lf becomes halfWe know that, T=2πImH Now T′=2π(I/8)(M/2)H=2πImH×14 T′=T14=T2or T′T=12