A radio wave undergoes a phase shift of 180 degrees when it reflects from the calm surface of the ocean. In early days of radioastronomy, Australian Astronomers observed the interference between a radio wave arriving at the their antena on a direct path from the sun and on a path involving one reflecting on the sea surface. If their antenna was located on the coastline 25m above the sea level and the radio waves had a frequency of 60 MHZ, find the least angle above the horizon for the sun that results in destructive interference of the waves at the receivng antenna.(adsbygoogle = window.adsbygoogle || []).push({});

The identity cos 2θ = 1-2sin^2θ

Ok, so that is the problem right now i have a diagram and understand destructive interference will occur when (n - 1/2 )λ

Wavelength in this situation is

V = Fλ

therefore λ = 60x10^6 / c

λ = 5m

the attachment is of my current diagram ( sorry for the crude drawings, only had paint avalible).

Cheers.

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# Homework Help: Sun Interference astronomy question

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