Question

Two short magnets placed along the same axis with their like poles facing each other will repel each other with a force which varies inversely as

• A. Distance
• B. Square of distance
• C. Cube of distance
• D. Fourth power of distance

Answer 1

The correct option is B Square of distance

The force of repulsion between two like poles, or of attraction between unlike poles is given by

$F=\frac{{\mu }_0}{4\pi }\times \frac{m_1{m}_2}{r^2}$

Where $m_1$ and $m_2$ are the strengths of the poles, $r$ is the distance between the poles and ${\mu }_0$ is the permeability of free space.

You can see that force varies inversely with the square of distance.