The radii of curvature of both the surfaces of a lens are equal. How will its focal length and power change if one of the surfaces of the lens is made plane ?

Explanation

To solve the problem, we need to analyze how the focal length and power of a lens change when one of its surfaces is made plane. Let's break it down step by step.

### Step-by-Step Solution:

1. **Understanding the Lens Configuration**:
- Initially, we have a lens with two surfaces, both having equal radii of curvature, denoted as \( R_1 = R \) and \( R_2 = -R \) (the negative sign indicates the curvature direction).

2. **Using the Lens Maker's Formula**:
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