A light beam passes from medium 1 to medium 2. Show that the emerging beam is parallel to the incident beam.

Explanation

To show that the emerging beam is parallel to the incident beam when a light beam passes from medium 1 to medium 2, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Setup**:
- Consider two media: Medium 1 (with refractive index \( \mu_1 \)) and Medium 2 (with refractive index \( \mu_2 \)).
- Let an incident ray strike the boundary between these two media at an angle \( I_1 \).

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