Q. The de Broglie wavelength of electron of $He ^{+}$ion is $3.329 \, \mathring{A}$. If the photon emitted upon deexcitation of this $He ^{+}$ion is made to hit $H$-atom in its ground state so as to liberate electron from it, what will be the de-Broglie's wavelength of photoelectron.
Structure of Atom
Solution: