A ray of light is incident on a plane mirror at an angle of incidence of `30^@`. The deviation produced by the mirror is

Options

A. `30^(@)`
B. `60^(@)`
C. `90^(@)`
D. `120^(@)`

Explanation

To solve the problem of finding the deviation produced by a plane mirror when a ray of light is incident at an angle of incidence of \(30^\circ\), we can follow these steps:

### Step 1: Understand the Concept of Deviation
The deviation produced by a mirror is defined as the angle between the direction of the incident ray and the direction of the reflected ray. For a plane mirror, the deviation can be calculated using the formula:
\[ \text{Deviation} (\delta) = 180^\circ - 2\theta \]
where \(\theta\) is the angle of incidence.

### Step 2: Identify the Given Information
From the question, we know:
- Angle of incidence (\(\theta\)) = \(30^\circ\)

### Step 3: Substitute the Value into the Deviation Formula
Now, we will substitute the value of \(\theta\) into the deviation formula:
\[ \delta = 180^\circ - 2 \times 30^\circ \]

### Step 4: Perform the Calculation
Calculate \(2 \times 30^\circ\):
\[ 2 \times 30^\circ = 60^\circ \]
Now substitute this back into the equation for deviation:
\[ \delta = 180^\circ - 60^\circ \]
\[ \delta = 120^\circ \]

### Step 5: State the Final Answer
The deviation produced by the mirror is:
\[ \delta = 120^\circ \]