Light travels in straight lines and very fast, faster than sound. We see objects because they reflect light into our eyes, while shadows are formed when light is blocked. There are two main types of reflection - specular reflection off smooth surfaces like mirrors, and diffuse reflection off rough surfaces. The law of reflection states that the incident ray, reflected ray, and normal to the surface all lie in the same plane, with the angle of incidence equaling the angle of reflection.

1. REFLECTION OF LIGHT

2. Light

9. How do we see objects?

11. Reflection

20. The Law of Reflection The incident ray, the reflected ray, and the normal to the surface all lie in the same plane, and the angle of reflection θ r equals the angle of incidence θ i.