$(20$pts$)$ Problem $27\mathrm{.}29($Giancoli$).$ A helium ion $($Q $=+2$e$)$ whose mass is $6\mathrm{.}6\backslash$times $1027$ kg is accelerated by a voltage of $5200$ V$.$ a$)$ What is its speed? b$)$ What will be its radius of curvature if it moves in a plane perpendicular to a uniform $0\mathrm{.}340-$T field? c$)$ What is its period of revolution?