Optics or Light

Optics
1) Reflection and Refraction of Light

Introduction to Light

 Light: A form of energy that enables us to see objects. It travels in straight lines and exhibits wave and
particle properties.
 Speed of Light: Approximately in a vacuum.

Reflection of Light
 Reflection: The phenomenon of light bouncing off a surface.

Laws of Reflection

1. The angle of incidence (θᵢ) is equal to the angle of reflection (θᵣ).
2. The incident ray, the reflected ray, and the normal to the surface all lie in the same plane.




Types of Reflection

1. Regular Reflection: Occurs on smooth surfaces; reflected rays are parallel.
2. Diffuse Reflection: Occurs on rough surfaces; reflected rays scatter in different directions.

Key Terms

 Incident Ray: The incoming ray striking a surface.
 Reflected Ray: The ray bouncing off the surface.
 Normal: A perpendicular line to the surface at the point of incidence.
 Angle of Incidence (θᵢ): The angle between the incident ray and the normal.
 Angle of Reflection (θᵣ): The angle between the reflected ray and the normal.

, Optics
Applications

 Mirrors (plane, concave, convex)
 Periscopes
 Kaleidoscopes

Refraction of Light
 Refraction: The bending of light as it passes from one transparent medium to another with a different optical
density.

Laws of Refraction

1. The incident ray, the refracted ray, and the normal to the surface all lie in the same plane.
2. The ratio of the sine of the angle of incidence (θᵢ) to the sine of the angle of refraction (θᵣ) is constant:

Snell’s Law: