1. Light at a Surface: Important terms:
Reflection, refraction, transmission, transparent, translucent, opaque, absorption

2. Reflection Law of Reflection: Angle of Incidence: Angle of Reflection:
Light will always reflects from a surface at the same angle in which it hits the surface.
Angle of Incidence:
The angle at which light hits a surface.
Angle of Reflection:
The angle at which light is reflected by a surface.

3. Specular Reflection: Diffuse Reflection:
Reflection from a smooth surface.
Ex: Mirror, any smooth shiny surface.
Diffuse Reflection:
Reflection of light from a rough surface.
Ex: Brick wall

4. Transmission of Light Transmission: Transparent Translucent Opaque
When light passes through matter.
Transparent
Translucent
Opaque

5. Transparent: When light passes easily through a material it is said to be transparent. Ex: water, air, glass

6. Translucent: When matter transmits some, but not all the light that hits it. Ex: wax paper

7. Opaque: When mater does not transmit any light
Opaque: When mater does not transmit any light. You cannot see through it. Ex: your desk, your textbook

8. Refraction: When light passes from one medium to another (from air to water for example), it is called refraction.