Answer Happy

The figure illustrates a number of optical lenses made of glass with index of refraction n. An equation from which the focal length of each lens in air can be calculated is: 1/f = (n-1)= 1/r1 + 1/r2) where ri and r2 are the magnitudes of the radii of curvature of the lens surfaces. r1 r2 0 r2 r1 z r2 r2 r1 ri Y Х ... Indicate the signs which are appropriate for the 1/r1 and 1/r2 terms in that equation: For lens y, the respective signs of 1/r2 and of 1/r1 are ✓ For lens X, the respective signs of 1/r1 and of 1/r2 are For lens Z, the respective signs of 1/r2 and of 1/r1 are .... Think of Fermat's Principle. 000