Physics Question from JEE Main 2025 · 2 April, Shift 1

A monochromatic light is incident on a metallic plate having work function $\phi$. An electron, emitted normally to the plate from a point A with maximum kinetic energy, enters a constant magnetic field, perpendicular to the initial velocity of the electron. The electron passes through a curve and hits back the plate at a point B. The distance between A and B is:

(Given: the magnitude of the charge of an electron is $e$ and its mass is $m$, $h$ is Planck's constant and $c$ is the velocity of light. Take the magnetic field to exist throughout the path of the electron.)