# Diopters homework problem

## Homework Statement

A prescription for a corrective lens calls for +1.50 diopters. The lensmaker grinds the lens from a "blank" with n = 1.46 and a preformed convex front surface of radius of curvature of 19.0 cm. What should be the radius of curvature of the other surface?

## Homework Equations

$$\frac{1}{f} = (n-1)\left ( \frac{1}{R_1} - \frac{1}{ R_2} \right )$$

## The Attempt at a Solution

1.5=(1.46 - 1)(1/19 - 1/x)

(1.5/.46) - 1/19 = 3.208
-1/3.208 = -.3117

which is wrong
am i doing this right cause i dont think i am