Reflection in a plane mirror

O/L Science · G.C.E. Ordinary Level · Grades 10–11

Aim

To verify the law of reflection: angle of incidence = angle of reflection.

Apparatus

• A plane mirror
• Ray box or pins
• Protractor and paper

Method

1. Stand the mirror on a line drawn on paper.
2. Draw the normal at right angles to the mirror.
3. Send a ray at an angle and mark the reflected ray.
4. Measure the angle of incidence i and angle of reflection r.
5. Repeat for 5 different angles.

Conclusion

i and r are equal within measuring error: i = r. The incident ray, the reflected ray and the normal lie in the same plane.