Physics - Magnetism Question with Solution | TestHub

The magnetic force provides the necessary centripetal force for circular motion.

$qvB=\frac{m{v}^2}{r}$

$v=\frac{qBr}{m}$

The time period of one revolution is $T=\frac{2\pi r}{v}$.

Substituting $v$, we get $T=\frac{2\pi m}{qB}$.

The time taken for $10$ revolutions is $t=10T=10\times \frac{2\pi m}{qB}=\frac{20\pi m}{qB}$.

Answer: $20\pi m/qB$