What is the speed of a 680 eV electron?

Question

What is the speed of a 3.50 keV electron?

Answer 1

(1/2) m v^2 = 680 eV * 1.602*10^-19 Joules/eV

(1/2)(9.1*10^-31) v^2 = 680*1.6*10-19

v^2 =680*1.6*10-19 / (4.55*10^-31)