Consider a small light bulb,3 m to the left of a biconvex lens,which forms an image 2 m to the right of the lens.The lens is made of glass with index of refraction 1.4 and its two surfaces have equal radii of curvature.How far to the right of the lens would light from the Moon concentrate,if it was incident from the left?
A)0.12 m
B)0.45 m
C)2 m
D)0.96 m
E)1.2 m

Question

Quizplus · Accepted Answer

The lens formula is 1/f = (n-1)(2/R) for a biconvex lens with equal radii of curvature. Given n = 1.4, the focal length f can be calculated. Using the lens formula 1/f = 1/v - 1/u, where u = -3 m and v = 2 m, we find f. Then, for light from the Moon (u = ∞), the image distance v = f.

Consider a Small Light Bulb,3 M to the Left of a Biconvex