Reflection of Light Notes

Reflection of Light

Key Terms

• Incident Ray: A ray of light that travels from a light source and strikes the surface of a mirror.

• Reflected Ray: The light ray that bounces off the mirror after striking its surface.

• Normal: An imaginary line that is drawn perpendicular to the mirror's surface at the point where the incident ray makes contact.

• Angle of Incidence ($\theta_i$): The angle formed between the incident ray and the normal.

• Angle of Reflection ($\theta_r$): The angle formed between the reflected ray and the normal.

Law of Reflection

• For smooth reflecting surfaces, the angle of incidence is always equal to the angle of reflection:

Virtual Image Formation by Plane Mirrors

• Plane mirrors form images through reflection.

• Virtual images appear to be behind the mirror but no actual light originates from there.

Characteristics of Images Formed by Plane Mirrors

• Size: Same size as the object.

• Distance: Same distance behind the mirror as the object is in front.

• Type: Virtual (cannot be projected onto a screen).

• Orientation: Upright (not inverted).

• Lateral Inversion: Reversed left to right.

Steps for Drawing Virtual Images Using Ray Diagrams

1. Draw the object and the mirror.

2. Draw incident rays from the lowest and highest points of the object.

3. Draw and extend the reflected rays.

4. Connect the lines and draw the virtual image.

Summary

• Reflection is the bouncing back of light from a surface.

• The law of reflection states that the angle of incidence equals the angle of reflection for smooth surfaces.

• Plane mirrors form virtual, upright, same-sized, and laterally inverted images that appear to be the same distance behind the mirror as the object is in front.