Question

What is the critical frequency when the electron density in the F1 layer is 20×10^10/cm^3?

(a) 40.2GHz

(b) 4.02 MHz

(c) 40.2 MHz

(d) 40.2Hz

This question was addressed to me in unit test.

This interesting question is from Critical Frequency in division Virtual Height, Critical Frequency and Muf of Antennas

Answer 1

Right choice is (b) 4.02 MHz

To explain: Critical frequency \(f_c=9\sqrt{N\, max} \)

\(f_c =9\sqrt{20×10^{10}}=4.02MHz \)