[UPSC CSE 1991] Central Force Motion and Gravitation (Q128, 20M)

An electron with velocity 4 \times 10^6\text{ m/s} approaches a point nucleus from a great distance with an impact parameter 0.5 \times 10^{-10}\text{ m}. Calculate the angular momentum of the electron about the nucleus. Show that the electron scattering is S-wave scattering.