An alpha particle and proton enter a region of magnetic field which is perpendicular to their direction of motion. Find ratio of radius of circle described by them if they
(i) have same velocity
(ii) have same momentum
(iii) have same energy
(iv) are accelerated by same potential difference

Explanation

(i) `2 : 1`
(ii) `1 : 2`
(iii) `1 : 1`
(iv) `sqrt2 : 1`