A proton is fired from very far away towards a nucleus with charge Q = 120 e, 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 protonatits start is: (take the proton mass, $$m_p = \left(\frac{5}{3}\right) \times 10^{-27}$$ kg; $$h/e = 4.2 \times 10^{-15}$$ J.s/C; $$\frac{1}{4 \pi ε_0} = 9 \times 10^9$$ m/f; 1 fm = $$10^{-15}$$ m)