| A | B |
|---|
| Refraction | The bending of light waves due to a change in speed. |
| Lens | A transparent object with at least one curved side that causes light to bend. |
| Convex Lens | A lens that is thicker in the center than at the edges. |
| Concave Lens | A lens that is thicker at the edges than in the middle. |
| Law of Reflection | Regardless of the surface, the angle of incidence is equal to the angle of reflection. |
| Focal Point | Light rays that travel parallel to the optical axis and strike the mirror are reflected so that they pass through a single point on the optical axis. |
| Focal Length | The distance along the optical axis from the center of the mirror to the focal point. |
| Mirror | An object that forms an image by changing the direction of light rays. |
| Prism | Transparent object that is triangular with refracting surfaces at an acute angle with each other and that separates white light into a spectrum of colors. |
| Opaque | Materials that let no light pass through them. |
| Transparent | Materials let almost all light pass through them. |
| Translucent | Materials that let some, but not all, light will pass through. |
