$($a$)$

What voltage $($in V$)$ will accelerate electrons from rest to a speed of $6\mathrm{.}20105$ m$/$s$?$

V

$($b$)$

Find the radius of curvature $($in m$)$ of the path of a proton accelerated through this potential in a $0\mathrm{.}420$ T field. $($Assume the field is perpendicular to the direction of motion.$)$

m

Compare this with the radius of curvature of an electron accelerated through the same potential.

rpre

$=$