The electron density of E, F1, F2 layers of ionosphere is 2 * 10^11, 5 * 10^11 and 8 * 10^11 m^-3 respectively. What is the ratio of critical frequency for reflection of radiowaves ? 5 * 10^11 and 8 * 10^11 m^-3 respectively. What is the ratio of critical frequency for reflection of radiowaves [...]