Biology Forums - Study Force

A beam of alpha particles (q = +2e) is directed at a uranium (Z = 92) target.
The radius of a uranium nucleus is 7.4× 10−15 m. The closest approach between
the centres of an alpha particle to a stationary uranium nucleus is 30.0×10−15 m.
The kinetic energy of the incident alpha particle is closest to
(A) 4.5 MeV
(B) 6.0 MeV
(C) 7.5 MeV
(D) 9.0 MeV
(E) 10.5 MeV