Basic objective of this lecture is to present on Light and Its Uses. Light produced by electron bombardment of gas molecules. Phosphors absorb photons that are created when mercury gas gets zapped with electrons. The phosphors glow & produce light. Neon light – neon inside glass tubes makes red light. Other gases make other colors. Image is made from “real” light rays that converge at a real focal point so the image is REAL. It can be projected onto a screen because light actually passes through the point where the image appears.