A thin double convex glass lens (Ng = 1.56) while surrounded by air has a 10 cm focal length. If it is placed under water (Nw = 1.33) 100 cm beyond a small fish where will the fish's image be formed? I understand the second question, that's easy. What I'm confused on is how to set up the ratio of the focal length in air and the focal length in water with the lens makers formula.

Question

A thin double convex glass lens (Ng = 1.56) while surrounded by air has a 10 cm focal length. If it is placed under water (Nw = 1.33) 100 cm beyond a small fish where will the fish's image be formed?  I understand the second question, that's easy. What I'm confused on is how to set up the ratio of the focal length in air and the focal length in water with the lens makers formula.

anonymous · Answer

AH HA!!!! Never mind, I got it.