College Physics 10th Edition by Raymond Serway,Chris Vuille

Exercise 60

A Boy Scout starts a fire by using a lens from his eyeglasses to focus sunlight on kindling 5.0 cm from the lens. The Boy Scout has a near point of 15 cm. When the lens is used as a simple magnifier, (a) what is the maximum magnification that can be achieved and (b) what is the magnification when the eye is relaxed Caution: The equations derived in the text for a simple magnifier assume a "normal" eye.