If a convex lens were made out of very thin clear plastic filled with air, and were then placed underwater where n = 1.33 and where the lens would have an effective index of refraction n = 1, the lens would act in the same way
A) as a concave mirror in air.
B) as a concave lens in air.
C) as a convex lens in air.
D) as a flat refracting surface between water and air as seen from the water side.
E) as the glasses worn by a farsighted person.

Question

Quizplus · Accepted Answer

A lens' behavior depends on the difference in the index of refraction between the lens material and the surrounding medium. In this case, the lens (n = 1) has a lower index of refraction than the surrounding water (n = 1.33), which would cause it to diverge light rays similar to a concave lens in air. Convex lenses converge light rays, but because the lens' refractive index is lower than the water's, it acts oppositely to its design in air, thus behaving like a concave lens.

If a Convex Lens Were Made Out of Very Thin