Q. A bar magnet is oscillating in the Earth’s magnetic field with a period $T$. What happens to its period of motion if its mass is quadrupled?
A) Motion remains SHM with time period =$T$/2
B) Motion remains SHM and period remains nearly constant
C) Motion remains SHM with time period $= 2T$
D) Motion remains SHM with time period$= 4\ T$
Explanation
(c) When mass is quadrupled, $ie,$ made 4 times.
$I$ becomes four times. As $T \propto \sqrt{I}.$
$\therefore T$ becomes twice, $ie,$ motion remains SHM with time period $= 2T$.
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.