Question

What should be the minimum electron density in the ionosphere, for the sky wave propagation of a 9 MHz signal?
A. `1.5xx10^12//m^3`
B. `10^12//m^3`
C. `0.5xx10^12//m^3`
D. `0.8xx10^12//m^3`

Answer 1

Correct Answer - B
For the sky wave propagation of the given signal , the critical frequency is given by `v_c=9 (N_"max")^(1//2)`
`therefore v_c^2=81 (N_"max")`
`therefore N_"max"=v_c^2/81=(9xx10^6xx9xx10^6)/(81)=10^12`
`therefore N_"max"=10^(12) m^3`