Eyes: A nearsighted physicist cannot see things clearly beyond 90 cm from her eyes. What is the power of the contact lenses that will enable her to see very distant objects clearly?

Question

Quizplus · Accepted Answer

The power $P$ of the lenses needed can be calculated using the formula $P = \frac{1}{f}$, where $f$ is the focal length in meters. For a nearsighted person who cannot see beyond 90 cm (or 0.9 meters), the focal length of the corrective lens must be -0.9 meters (negative because it's a diverging lens for nearsightedness). Thus, $P = \frac{1}{-0.9} \approx -1.1$ diopters.

Eyes: a Nearsighted Physicist Cannot See Things Clearly Beyond 90