Dual Nature of Radiation

A proton is fired from very far away towards a nucleus with charge Q = 120e, where e is the electronic charge. It makes a closest approach of 10 fm to the nucleus. The de Broglie wavelength (in units of fm) of the proton at its start is _____.
(Take the proton mass, mp = (5/3) × 10−27 kg; h/e = 4.2 × 10−15 J.s/C;

1

4πε0

= 9 × 109 m/F; 1 fm = 1015 m.)