A proton and an alpha particle are projected with equal velocities into a perpendicular magnetic field. What will be the ratio of radius of the path traced by them?

1 : 2 2 : 1 1:16 1 : 1

1 : 1

Radius $ r = \frac{mv}{qB}$ ⇒ r ∝ 1/q qp : qα = 1 : 4 mα : mp = 4 : 1 rp : rα = qα : qp = 1 : 1