The inner bottom of a tub filled with water is stained with a mark. The water is filled to a height of 7 cm. Calculate the distance by which the stain appears to be raised. Refractive index of water is 1.33.

Explanation

To solve the problem of how much the stain appears to be raised when viewed from above the water surface, we can use the concept of apparent depth due to refraction. Here’s a step-by-step solution:

### Step 1: Understand the Problem
We have a tub filled with water to a height of 7 cm, and we need to find out how high the stain appears to be raised due to the refraction of light at the water-air interface.

### Step 2: Identify Given Values
- Actual depth of water (T) = 7 cm
- Refractive index of air (μ1) = 1 (approximately)
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