SOLUTION: A laser beam is transmitted with a "width" of 0.00200 degree. What is the diameter d of a spot of the beam on an object 258,000km distant?

Question 147441: A laser beam is transmitted with a "width" of 0.00200 degree. What is the diameter d of a spot of the beam on an object 258,000km distant?
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
A laser beam is transmitted with a "width" of 0.00200 degree. What is the diameter d of a spot of the beam on an object 258,000km distant?
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Draw the picture (an isosceles triangle)
Draw a perpendicular bisector forming two right triangles at the diameter line.
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Pick one of the triangles; it has angle 0.001 degree and base 258,000 km
Find the altitude (a)
tan(0.001) = a/258,000
a = 258000*tan(0.001)
a = 4.50 km
That is the radius of the beam.
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Diameter of the beam = 2*4.5 = 9 km
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Cheers,
Stan H.
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