(a-b) +L R = Simplifying Step 3 4(a-b) b.) For the convex lens in this lab, the same parameters apply: a The radius of curvature R for the convex lens follows the same equation you derived for the concave lens. However, you simply get a reversal of sign for R that follows from the sign convention for geometric optics. L/2 Step Reason d² + (L²/4) R = Result of Prelab 3, which applies here as well. 2d d = Considering the rectangular angle [(b- a) /4] + (L/4) Substituting step 6 with step 5 R = (b-a) (b-a) +L Simplification R = 4(b — а) c.) What is the small, but important difference between the last equation (concave lens) and the resulting equation here? What physical parameter of the lenses causes the difference between the two equations? Explain. The difference between the two equations is simply the value of d. In part A the lens width across the middle is smaller than in part b. That is why in the last equations, (a- b) of part a is changed to (b-a). 7.) What does the focal length of a lens depend on (Lens Maker's Equation)? Restate the equation for the focal length of a lens.

(a-b) +L R = Simplifying Step 3 4(a-b) b.) For the convex lens in this lab, the same parameters apply: a The radius of curvature R for the convex lens follows the same equation you derived for the concave lens. However, you simply get a reversal of sign for R that follows from the sign convention for geometric optics. L/2 Step Reason d² + (L²/4) R = Result of Prelab 3, which applies here as well. 2d d = Considering the rectangular angle [(b- a) /4] + (L/4) Substituting step 6 with step 5 R = (b-a) (b-a) +L Simplification R = 4(b — а) c.) What is the small, but important difference between the last equation (concave lens) and the resulting equation here? What physical parameter of the lenses causes the difference between the two equations? Explain. The difference between the two equations is simply the value of d. In part A the lens width across the middle is smaller than in part b. That is why in the last equations, (a- b) of part a is changed to (b-a). 7.) What does the focal length of a lens depend on (Lens Maker's Equation)? Restate the equation for the focal length of a lens.