A double convex lens has radii of curvature equal to 10 cm and 15 cm of the two faces. Given the focal length of lens is 12 cm, calculate the refractive index of glass.

Explanation

To find the refractive index of the glass used in a double convex lens with given radii of curvature and focal length, we can use the lens maker's formula. Let's go through the solution step by step.

### Step-by-Step Solution:

1. **Identify the Given Values:**
- Radius of curvature of the first surface, \( r_1 = 10 \, \text{cm} \) (positive for convex surface).
- Radius of curvature of the second surface, \( r_2 = -15 \, \text{cm} \) (negative for convex surface facing the incoming light).
- Focal length of the lens, \( f = 12 \, \text{cm} \) (positive for converging lens).
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