A proton, a deuteron and an α-particle having the same kinetic energy are moving in circular trajectories in a constant…..

Q. A proton, a deuteron and an α-particle having the same kinetic energy are moving in circular trajectories in a constant magnetic field. If r_p, r_d and rα denote respectively, the radii of the trajectories of these particles, then

(a) r_a = r_p < r_d

(b) r_a > r_d < r_p

(c) r_a = r_d > r_p

(d) r_p = r_d = r_a

Ans: (a)