A thin lens has a focal length of 10.00 cm for blue light. If the index of refraction for the lens material tends to decrease with increasing wavelength, what is the focal length of the lens for red light?

Question

Quizplus · Accepted Answer

The focal length of a lens is inversely proportional to the index of refraction. Since the index of refraction decreases with increasing wavelength, the focal length for red light (which has a longer wavelength than blue light) will be more than 10.00 cm.

A Thin Lens Has a Focal Length of 10