A light ray incidents on an equilateral triangle with an angle of `30^@`. Find the angle of deviation of the emergent light ray if the angle of emergence from the second surface is `70^@`.

Explanation

To solve the problem of finding the angle of deviation of the emergent light ray from an equilateral triangle prism, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Given Values:**
- Angle of incidence (i1) = 30 degrees
- Angle of emergence (i2) = 70 degrees
- Angle of the prism (A) = 60 degrees (since it is an equilateral triangle)
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