Q. The time period of a bar magnet suspended horizontally in the earth’s magnetic field and allowed to oscillate
A) Is directly proportional to the square root of its mass
B) Is directly proportional to its pole strength
C) Is inversely proportional to its magnetic moment
D) Decrease if the length increases but pole strength remains same
Explanation
(a) $T = 2\pi\sqrt{\frac{1}{MB_{H}}}$ and $I = \frac{w(l^{2} + b^{2})}{12};\ \therefore T \propto \sqrt{w}$
$(w =$ Mass of the magnet)
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.