Q. The magnetic field of a small bar magnet varies in the following manner by the influence of a magnet placed at a large distance d.
A) $\frac{1}{d}$
B) $\frac{1}{d^{2}}$
C) $\frac{1}{d^{3}}$
D) $\frac{1}{d^{4}}$
Explanation
(c) Magnetic field due to short magnet
$\ \ \ \ \ \ B = 10^{- 7}\frac{2M}{d^{3}}$
Or $B \propto \frac{1}{d^{3}}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.