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 10fm to the nucleus. The de-Broglie wavelength (in unit of fm) of the proton at its start is:
(take the proton mass, mp=(5/3)×10−27kg;h/e=4.2×10−15Js/C;
14πϵ0=9×109m/F;1fm=10−15m)