A tired physics professor can easily read the fine print of the financial page when the newspaper is held at arm's length, 57.5 cm from the eye. What should be the focal length of an eyeglass lens that will allow him to read at the more comfortable distance of 24.0 cm?

Explanation:

The person suffers from hypermetropia or long sightedness

object distance u = -24 cm

image distance v = - 57.5 cm

lens formula

1 / v - 1 / u = 1 / f

- 1 / 57.5 + 1 / 24 = 1 / f

- .01739 + .0417 = 1 / f

.02431 = 1 / f

f = 41 .13 cm

lens will be convex .

trig 15.3 cos

frequency or wavelenth of em radiation in a vacuum