Draw a ray from the object to the lens that is parallel to the principal axis. Once through the lens, the ray should pass through the principal focus. Draw a ray which passes from the object through ...

We compare and contrast concave and convex lenses by drawing ray diagrams. In this Closer Look segment on Lenses, we compare and contrast concave and convex lenses by drawing ray diagrams and ...

Science presenter Jon Chase explains total internal reflection. He demonstrates how total internal reflection can make a coin disappear inside a glass of water and bend a laser beam. The second ...