Q 12-04-174JEE MainJEE Main 2021 (27 Aug, Shift 1)Easy
Two ions of masses $4$ amu and $16$ amu have charges $+2e$ and $+3e$ respectively. These ions pass through the region of the constant perpendicular magnetic field. The kinetic energy of both ions is the same. Then:
Answer: (B) lighter ion will be deflected more than heavier ion
$r = \dfrac{mv}{qB} = \dfrac{\sqrt{2mK}}{qB} \propto \dfrac{\sqrt{m}}{q}$ for equal $K$.
Lighter: $\dfrac{\sqrt{4}}{2} = 1$; heavier: $\dfrac{\sqrt{16}}{3} = \dfrac{4}{3}$.
The lighter ion moves on the smaller circle, so it is deflected more.
Solution by Sreeraj P, M.Sc Physics