The plane surface of a plano-convex lens of focal length 60 cm is silvered. A point object is placed at a distance 20 cm from the lens. Find the position and nature of the final image formed.

Explanation

To solve the problem step by step, let's break it down:

### Step 1: Understand the System
We have a plano-convex lens with a focal length of \( f = 60 \, \text{cm} \). Since the plane surface is silvered, it acts like a convex mirror. The focal length of a convex mirror is considered negative.

### Step 2: Determine the Focal Length of the System
The focal length of the plano-convex lens when silvered can be calculated as follows:
- The focal length of the convex surface (lens) is \( f_1 = 60 \, \text{cm} \).
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