Sound WavesHard
Question
In short wave communication wave of which of the following frequencies will be reflected back by the ionospheric layer having electron density 1011 per m3 ?
Options
A.2 MHz
B.10MHz
C.12 MHz
D.18 MHz
Solution
If n be the frequency beyond which it will leakout to the upper region of atmosphere (this limit is known as critical) frequency then
n = 9 √N
N is the charge density of ionospere n = 9
= 9 × 105 × 3.12 = 2.7 × 106
   = 2MHz
n = 9 √N
N is the charge density of ionospere n = 9
= 9 × 105 × 3.12 = 2.7 × 106    = 2MHz
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