A ray of light incident on an equilateral triangular glass prism of `mu = sqrt(3)` moves parallel to the base of the prism inside it. What is the angle of incidence for this ray ?

Explanation

To solve the problem, we need to find the angle of incidence for a ray of light striking an equilateral triangular prism with a refractive index (μ) of √3, such that the ray moves parallel to the base of the prism inside it.

### Step-by-Step Solution:

1. **Understand the Geometry of the Prism:**
- An equilateral triangle has all angles equal to 60 degrees. Therefore, each angle of the prism is 60 degrees.

2. **Identify the Incident Ray and Refraction:**
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