NTA Abhyas JEE Main2020PhysicsCommunication SystemPractice
The maximum frequency for reflection of sky waves from a certain layer of the ionosphere is found to be f max = 9 ( N max ) 1 / 2 , where N max is the maximum electron density at that layer of the ionosphere. On a certain day, it is observed that signals of frequencies higher than 8 MHz are not received by reflection from the F 2 layer of the ionosphere. Estimate the maximum electron densities of the F 2 layers on th
Options
- A7 . 9 × 10 11 m - 3
- B8 . 9 × 10 11   m - 3
- C1 . 9 × 10 11   m - 3
- D7 . 1 × 10 11   m - 3
Correct answer
A. 7 . 9 × 10 11 m - 3
Step-by-step solution
The maximum frequency for reflection of sky waves f max = 9 ( N max ) 1 / 2 where N max is a maximum electron density. For F 2 layer, f max = 8 MHz So, 8 × 10 6 = 9 ( N max ) 1 / 2 maximum electron density, N max = 8 × 10 6 9 2 = 7 · 9 × 10 11 m - 3