Part 3/6:
Here, (\alpha) represents the angle of incidence, (\beta) the angle of refraction, and (k) is the index of refraction of the medium—in this case, water.
Analyzing Angles of Deviation
To calculate how angles change as light exits the raindrop, we define the angle of deviation as how much the light deviates from its original path. This angle can be computed as follows:
The light is first refracted at an angle when it enters the drop.
It reflects off the back surface.
Finally, it refracts again as it exits into the air.
Summing these angles leads to a complex formula that ultimately allows us to determine where the light exits the raindrop, which significant contributes to the observable location of the rainbow.