A 50MHz sky wave takes 4.04 ms to reach a receiver via retransmission from a satellite 600km above earht's surface. Assuming re-transmission time by satellite negligible, find the distance between source and reciever.

Options

A. 606km
B. 170km
C. 340km
D. 280km

Answer

B

Explanation

Here Total time taken, `t=4.04 ms=4.04xx10^(-3)s` Let x be the distance satellite from the surface of earth
Total time taken (t)`=("Total distance travelled"(2x))/("Speed of electromagnetic waves"(c))`
` therefore x=(ct)/(2)=((3xx10^(8))(4.04xx10^(-3))/(2)=6.06xx10^(5)m=606km`
`therefore x=(ct)/(2)=((3xx10^(8))(4.04xx10^(-3)))/(2)=6.06xx10^(3)m=606km`
Let T be the source of electromangetic waves (i.e. transmitter), R be receiver and S be sate as shown in figure.

`d^(2)xxx^(2)-h^(2)=(606)^(2)-(600)^(2)`
`therefore d= 85.06km`
Distance between source and receiver
`=2d=2xx85.06=170km `