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?
A) 1.1 diopters
B) -1.1 diopters
C) -1.7 diopters
D) -2.2 diopters
E) 2.2 diopters

Question

Quizplus · Accepted Answer

To calculate the power of the required contact lens, we use the following formula:
Power of lens (in diopters) = 1/focal length (in meters)
Here, the physicist cannot see objects beyond 90 cm, which is 0.9 meters. So, the focal length required for the contact lens should be:
focal length = 0.9 meters
Substituting this value in the formula above, we get:
Power of lens = 1/0.9 = 1.11 diopters
However, since the physicist is nearsighted, the lens should be a concave lens (or a diverging lens), which has a negative power. So, the power of the required contact lens is:
Power of lens = -1.1 diopters (closest option is B))

A Nearsighted Physicist Cannot See Things Clearly Beyond 90 Cm