Past exam of the MPhil in micro- and nanotechnology enterprise course of the University of Cambridge / 2021 / Paper 2 / Section B / 20 / iv / b / Solution

Substituting $r_c=\hslash k_F/(e|B|)$ into $L=2j{r}_c$ givesUsing the density-derived Fermi wave vector gives the first three peak magnitudesThe equally spaced sequence follows from the number of reflected half-orbits, not from successive quantum Hall fillings. The field polarity selecting a given injector–collector orientation follows from the Lorentz force direction.