Manipal Entrance Test 2020 Physics Paper

Time period of a suspended magnet is given by T=2π√‌

l

MB

where, I= moment of inertia of the magnet about the point of suspension.
M= magnetic moment
B= magnetic field
When the magnet is broken in length
T2′=2π√‌

l′

M′B

Here, m and m ' are the masses of the magnet and L and L's are their lengths.
⇒‌‌T′=‌

T

2

=‌

4

2

=2s