AIIMS2005PhysicsCommunication System
For skywave propagation of a 10 MHz signal, what should be the minimum electron density in ionosphere?
Options
- A1.2 10¹² ~m ⁻³
- B10^6 ~m ⁻³
- C10¹⁴ ~m ⁻³
- D10²² ~m ⁻³ .
Correct answer
A. 1.2 10¹² ~m ⁻³
Step-by-step solution
The critical frequency of a sky wave for reflection from a layer of atmosphere is given by f_c=9 (N_ )^ 1 / 2 where N is the density of electron / m ^3 . aligned 10 10^6 & =9 (N_ )^ 1 / 2 N_ & = ( 10 10^6 9 )^2 1.2 10¹² ~m ⁻³ aligned