State one important factor which affects the critical angle of a given medium.

Explanation

To solve the question, we need to identify one important factor that affects the critical angle of a given medium. The critical angle is the angle of incidence above which total internal reflection occurs when light travels from a denser medium to a less dense medium.

### Step-by-Step Solution:

1. **Understand the Concept of Critical Angle**:
The critical angle is defined as the angle of incidence at which light is refracted at an angle of 90 degrees when passing from a denser medium to a less dense medium.

2. **Identify the Factors Affecting Critical Angle**:
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