Q 12-04-148JEE MainJEE Main 2022 (25 Jul, Shift 1)Medium
Two charged particles, having the same kinetic energy, are allowed to pass through a uniform magnetic field perpendicular to the direction of motion. If the ratio of radii of their circular paths is $6 : 5$ and their respective masses ratio is $9 : 4$, then the ratio of their charges will be
Answer: (B) $5 : 4$
$r = \dfrac{\sqrt{2mK}}{qB}\Rightarrow q\propto\dfrac{\sqrt m}{r}$ for equal $K$:
$$\frac{q_1}{q_2} = \sqrt{\frac94}\times\frac56 = \frac32\times\frac56 = \frac54$$
Solution by Sreeraj P, M.Sc Physics