Question

Name the three different modes of propagation of electromagnetic waves. Explain, using a proper diagram the mode of propagation used in the frequency range above $40MHz$.

Answer 1

The three modes of propagation are-
(i) Ground waves

(ii) Space waves

(iii) Sky waves

The ionosphere acts as reflector for certain frequencies(3Hz to 40Hz).

Above 40Hz, waves penetrate the ionosphere and escape.