JEE Main & Advanced
Physics
Communication System / संचार तंत्र
Question Bank
Communication
question_answer
In short wave communication waves of which of the following frequencies will be reflected back by the ionospheric layer, having electron density 1011 per m3 [AIIMS 2003]
A) 2 MHz
B) 10 MHz
C) 12 MHz
D) 18 MHz
Correct Answer:
A
Solution :
By using \[{{f}_{c}}\approx 9{{({{N}_{\max }})}^{1/2}}\]Þ \[{{f}_{c}}\approx 2\,MHz\]