Two vertical plane mirrors are inclined at an angle of `60^(@)` with each other. A ray of light travelling horizontally is reflected first from one mirror and then from the other. The resultant deviation is

Options

A. `60^@`
B. `120^@`
C. `180^@`
D. `240^@`

Explanation

To solve the problem of finding the resultant deviation when a ray of light is reflected between two mirrors inclined at an angle of \(60^\circ\), we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Setup**:
- We have two vertical mirrors (let's call them Mirror 1 and Mirror 2) inclined at an angle of \(60^\circ\) to each other.
- A ray of light is traveling horizontally towards Mirror 1.

2. **Identify the Angle of Incidence**:
- Since the ray is horizontal and the mirrors are vertical, the angle of incidence on Mirror 1 is \(0^\circ\) (the ray is parallel to the surface of the mirror).

3. **Reflection from Mirror 1**:
- According to the law of reflection, the angle of reflection is equal to the angle of incidence. Therefore, the ray will reflect off Mirror 1 at an angle of \(0^\circ\) (it will continue horizontally).

4. **Determine the Angle of Incidence on Mirror 2**:
- After reflecting off Mirror 1, the ray travels towards Mirror 2. The angle between the ray and the normal to Mirror 2 is \(60^\circ\) (the angle between the two mirrors).
- Thus, the angle of incidence on Mirror 2 is \(60^\circ\).

5. **Reflection from Mirror 2**:
- Again, applying the law of reflection, the angle of reflection from Mirror 2 will also be \(60^\circ\).

6. **Calculate the Total Deviation**:
- The total deviation caused by the two reflections can be calculated as follows:
- The ray initially travels in a straight line (0 degrees deviation).
- After reflecting off Mirror 1, it continues horizontally (0 degrees deviation).
- After reflecting off Mirror 2, it deviates by \(60^\circ\) to the left.
- The total deviation from the original path is \(180^\circ - 60^\circ = 120^\circ\).

7. **Final Result**:
- The resultant deviation of the ray after reflecting off both mirrors is \(120^\circ\).

### Summary:
The resultant deviation of the ray of light after reflecting off both mirrors is \(120^\circ\).