A transmitting antenna of height 20 ~m and the receiving antenna of height h are separated by a distance of 40 ~km for satisfactory communication in line of sight (Los) mode. Then the value of h is (Give, radius of earth is 6400 ~km .)

Step-by-step solution

Given, height of transmitting antenna h_T=20 ~m , distance of LOS, d_m=40 ~km As maximum distance of line of sight mode d_m= 2 R h_T + 2 R h_R putting the given values, we get aligned 40= & 2 6.4 10^3 20 10⁻³ & + 2 6.4 10^3 h_R 10⁻³ 40 & =16+ 2 6.4 10^3 10⁻³ h_R 2 6.4 h_T & =24 24 h_T & =45 ~m aligned Hence, the correct option is (b).