Optics usually describes the behaviour of visible, ultraviolet, and infrared light.
Because light is an electromagnetic wave, other forms of electromagnetic radiation such as X-rays, microwaves, and radio waves exhibit similar properties.
This is the 1st lesson in the series, "Light and Lenses." It investigates the nature and meaning of images. The lesson defines images as a visual representation of an object that actually looks like the object. The lesson identifies and explains different optical devices and different types of images.
This is the 2nd lesson the series, "Light and Lenses." This lesson shows how to draw ray diagrams showing how light is refracted through convex lenses and demonstrates how to use the diagrams to determine size, position and nature of an image formed by a convex lens.