How is the picture formed on a TV screen ?
The T.V. antenna receives the radio waves, and passes it into the T.V. set.
The screen of the set is made of a sheet of glass with a special phosphor coating on the back. The screen is made up of tiny chemical dots which are arranged in a groups of three- a red, a green and a blue in a colour. T.V or light and dark parts in a black and white T.V. at the back of the screen, there is a big glass tube called Cathode Ray Tube (CRT). At the back of this tube are three electron guns in a colour T.V. and a single gun in a black and white T.V. these guns fire electrons which illuminate the dots on the screen in a pattern received by the electric signal. These tiny flashes build up the picture on the screen so fast that we cannot see them individually. The electron gun move too fast for the eye to follow.
