A pond of depth 20 cm is filled with water of refractive index `4//3`. Calculate apparent depth of the tank when viewed normally.

Explanation

To solve the problem of finding the apparent depth of a pond filled with water, we can use the relationship between real depth, apparent depth, and the refractive index of the medium.

### Step-by-Step Solution:

1. **Identify the Given Values**:
- Real depth (l) = 20 cm
- Refractive index (n) = 4/3

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