Physics - Current Electricity Question with Solution | TestHub

A proton is fired from very far away towards a nucleus with charge $Q=120\mathrm{e}$, 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 proton at its start is : ( take the proton mass, $\mathrm{mp}=(5/3)\times 10^{-27}\mathrm{kg};\mathrm{h}/\mathrm{e}=4.2\times 10^{-15}\mathrm{J}.\mathrm{s}/\mathrm{C};\frac{1}{4\pi {\epsilon }_0}=9\times 10^9\mathrm{m}/\mathrm{F};1\mathrm{fm}=10^{-15}\mathrm{m})$