Two towers on top of hills are 40Km apart . The line joining them passes 50m above a hill halfway between the towers .Longest wavelength of radio waves which can be sent between the towers without appreciable diffraction is ......
Answers
ANSWER
Distance between the towers is 40km.
Height of the line joining the hills is d=50m.
Thus, the radial spread of the radio waves should not exceed 50 m.
Since the hill is located halfway between the towers, Fresnel’s distance can be obtained.
Z
P
=20km
Aperture is a=d=50m
Fresnel’s distance is given by the relation,
Z
P
=a
2
/λ=2×10
4
λ=a
2
/Z
P
=12.5cm
Explanation:
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Answer:
12.5cm
Explanation:
Distance between the towers is 40km.
Height of the line joining the hills is d=50m.
Thus, the radial spread of the radio waves should not exceed 50 m.
Since the hill is located halfway between the towers, Fresnel’s distance can be obtained.
Z P
=20km
Aperture is a=d=50m
Fresnel’s distance is given by the relation,Z P
=a 2 /λ=2×10)4
λ=a 2 /Z P
=12.5cm