A bar magnet is oscillating in the earth's magnetic field with a period T. What happens to its period and motion if its mass is quadrupled

Options

A. Motion remains S.H.M. with time period =2T
B. Motion remains S.H.M. with time period =`4T`
C. Motion remains S.H.M. and period remains nearly constant
D. Motion remains S.H.M. with time period =`T/2`

Answer

A

Explanation

As `T prop sqrt(I)`, where I= moment of inertia
`=(wL^(2))/12impliesTpropsqrt(w)` (w= Mass of magnet. If wrarr quadrupled, then Trarr doubled, i.e., `T^(')=2T`