Question

A ray of light is incident on a plane mirror at an angle of incidence of 15°. The deviation in the ray produced by the mirror is:

• A. 30°
• B. 60°
• C. 120°
• D. 150°

Answer 1

The Correct Option is A

Step 1: Analyze incident angle and mirror deviation:
According to the law of reflection, the angle of incidence equals the angle of reflection when light hits a plane mirror. Deviation is the difference between the incident and reflected ray angles.

Step 2: Formulate deviation for a plane mirror:
The total deviation \( \delta \) from a plane mirror is calculated by: \[ \delta = 2 \times \text{angle of incidence} \] This formula holds because the angle between the incident and reflected rays is double the angle of incidence.

Step 3: Input the given angle:
With an angle of incidence of 15°, the deviation is calculated: \[ \delta = 2 \times 15° = 30° \] Therefore, the mirror produces a deviation of 30°.

Step 4: Final Result:
The deviation of the ray by the plane mirror is 30°.