Circular Halos
Classical Mechanics
Level
2
Halos, as shown, are a frequent optical phenomenon. The most common is the circular halo (22° halo). What is the best explanation for this occurrence?
Light is reflected by rain at lower altitudes
Light is refracted by hexagonal ice crystals in the atmosphere
Light refracted by raindrops is dispersed in a circular array
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1 solution
It has to be the ice crystals. Water drops result in rainbows with a radius of 42 degrees. The smaller angle of the halo is due to the greater refractive index of ice.