Radio waves emitted from an antenna are picked up by a radar after reflection from an aircraft in 4 x 10\(^{-3}\)S. How far is the aircraft from the antenna? [c = 3 x 10\(^8\)ms\(^{-1}\) ]
6.0 x 10\(^2\)km
1.2 x 103km
3.0 x 103km
6.0 x 10 5km
Explanation
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Discussions (27)
Reflected sound is echo
So use the formula for echo which is
Vt = 2d ( distance is double because of reflection)
Using vt =2d
d = vt/2
d = 0.004x300,000,000
d = 600,000 or 6x10^5 m
Reflected sound is echo
So use the formula for echo which is
Vt = 2d ( distance is double because of reflection)
Using vt =2d
d = vt/2
d = 0.004x300,000,000
d = 600,000 or 6x10^5 m.
Note: the only mistake in the options is that they used km instead of meters.
Option D should be correct but it should be M not Km.
The question is wrongly composed:
in the question the time give was 4x10^-3 but when i solved with that their was no answer. but in your explanation the time giving is 2x10^-3.
so it should please be corrected.
the correct ans is A becos the wave was read after its reflection by the airplane therefore it covered a distance of 2*d
Hence, your formula would be;
2*d=v*t
Upon getting your ans, converting to km would give you option A i.e 0.6*10^3 or 6*10^2
