Question

A transmitting antenna of height h and the receiving antenna of height 45 m are separated by a distance of 40 km for satisfactory communication in line of sight mode. Then the value of h is (given radius of the earth is 6400 km):

पर्याय

• 10 m

• 20 m

• 50 m

• 80 m

Answer 1

20 m

Explanation:

d = `sqrt(2"Rh"_"r") + sqrt(2"Rh"_"R")`

∴ 40 × 1000 = `sqrt(2 xx 6.4 xx 10^6 xx "h") + sqrt(2 xx 6.4 xx 10^6 xx 45)`

40 × 10³ = `sqrt(2 xx 6.4 xx 10^6 xx "h") + 24 xx 10^3`

h = `([(40 - 24)10^3]^2)/(2 xx 6.4 xx 10^6)` = 20 m