A light ray is incident normally on a plane mirror.
What is the angle of incidence?

Explanation

To solve the question regarding the angle of incidence when a light ray is incident normally on a plane mirror, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Terms**:
- The **angle of incidence** is defined as the angle between the incident ray and the normal to the surface at the point of incidence.
- The **normal** is an imaginary line that is perpendicular to the surface of the mirror at the point where the light ray strikes.

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