A lens is made with a focal length of -40 cm using a material with index of refraction 1.50.A second lens is made with the SAME GEOMETRY as the first lens,but using a material having refractive index of 2.00.What is the focal length of the second lens?
A) -40 cm
B) -80 cm
C) -53 cm
D) -20 cm
E) -30 cm

Question

Quizplus · Accepted Answer

The focal length of a lens is inversely proportional to the index of refraction of the material used to make the lens. Therefore, the focal length of the second lens will be -40 cm / 2.00 = -20 cm.

A Lens Is Made with a Focal Length of -40