A) \[5\,\,MHz\]
B) \[6\,\,GHz\]
C) \[5\,\,kHz\]
D) \[500\,\,MHz\]
Correct Answer: A
Solution :
The ionosphere extends from a height of \[80\,\,km\] to\[300\,\,km\]. The refractive index of ionosphere is less than its free space value. That is, it behaves as a rarer medium. As we go deep into the ionosphere, the refractive index keeps on decreasing. The bending of beam (away from the normal) will continue till it reaches critical angle after which it will be reflected back. The different points on earth receive signals reflected from different depths of the ionosphere. There is a critical frequency\[{{f}_{c}}(5\] to \[100\,\,MHz)\] beyond which the waves cross the ionosphere and do not return back to earth.
You need to login to perform this action.
You will be redirected in
3 sec
