Question

3. (a) Assume that a light ray incident from air on a spherical raindrop of radius R at angle measured with respect to the surface normal undergoes one internal reflection before leaving the raindrop, as shown below. refraction Incident ray Internal reflection A refraction Use the area above to show that if ; = 0 and 2 = @it, then the total deflection angle 8 = 8 + 8 + 83 of the light ray is (in radians): 8 = 2(0-0) + (ft - 20.) The deflection angle 8 is the angle between the incident ray and the outgoing ray, and e, is the angle of refraction for the light ray incident from air and entering water. (b) Eliminate , from the equation for 8 and express 8 in terms of 0 Nair, and nwater- (c) If @ = 60°, is the internal reflection a total internal reflection?

Answer 1

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