If a ray of light incident on a plane mirror is such that it makes an angle of `30^@` with the mirror, then the angle of reflection is

Options

A. `30^@`
B. `45^@`
C. `55^@`
D. `60^@`

Explanation

To solve the problem, we need to determine the angle of reflection when a ray of light makes an angle of \(30^\circ\) with a plane mirror.

### Step-by-Step Solution:

1. **Understanding the Setup**:
- A ray of light is incident on a plane mirror.
- The angle given (30°) is the angle between the incident ray and the mirror surface.

2. **Identifying the Normal**:
- The normal is an imaginary line that is perpendicular to the surface of the mirror.
- Since the mirror is flat, the normal line will be at a \(90^\circ\) angle to the mirror surface.

3. **Finding the Angle of Incidence**:
- The angle of incidence (I) is measured between the incident ray and the normal.
- Since the angle with the mirror is \(30^\circ\), we can find the angle of incidence using the relationship:
\[ I + 30^\circ = 90^\circ \]
- Rearranging gives:
\[ I = 90^\circ - 30^\circ = 60^\circ \]

4. **Applying the Law of Reflection**:
- According to the law of reflection, the angle of incidence is equal to the angle of reflection (R).
- Therefore, we have:
\[ R = I = 60^\circ \]

5. **Conclusion**:
- The angle of reflection is \(60^\circ\).

### Final Answer:
The angle of reflection is \(60^\circ\).

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