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 Js/C; 4πε01=9×109 m/F; 1 fm=10−15 m [2012-1])