1. The problem statement, all variables and given/known data A biconvex lens with radius of curvature 15 cm has a focal length of 15 cm in air. What is its focal length if it is submerged in water (n=1.33)? 2. Relevant equations 1/f = (n-1)(1/R1 - 1/R2) 3. The attempt at a solution 1/f = 1/0.15 = (n-1)(2/0.15) Solving for n gives n = 1.5 So the new equation will be: 1/f = (1.5 - 1.33)(2/0.15) = 2.27 f = 0.44 What am I doing wrong?