E∝1r\mathrm{E} \propto \frac{1}{\mathrm{r}}E∝r1
E∝1r2E \propto \frac{1}{r^{2}}E∝r21
E∝1r3E \propto \frac{1}{r^{3}}E∝r31
E∝1r4E \propto \frac{1}{r^{4}}E∝r41