A proton and an α -particle (with their masses in the ratio of 1: 4 and charges in the ratio of 1: 2 ) are accelerated from rest through a potential…

A proton and an $\displaystyle \alpha$-particle (with their masses in the ratio of $\displaystyle 1$ : $\displaystyle 4$ and charges in the ratio of $\displaystyle 1: 2$ ) are accelerated from rest through a potential difference V. If a uniform magnetic field (B) is set up perpendicular to their velocities, the ratio of the radii $\displaystyle \mathrm{r}_{\mathrm{p}}: \mathrm{r}_\alpha$ of the circular paths described by them will be :