Sample Material of Our Online Coaching Programme
Subject: General Science
Topic: Gist of What, Why and How
Radars Work
The word radar stands for radio detecting and ranging. It makes use of very short radio waves called microwaves. Radars work to find out how far away an Object is and in case of a moving object in what direction it is moving and at what speed.
Color TV Picture Produced
The picture on a television screen is nothing but a pattern of glowing dots, or pixels. The pixels are made up of fluorescent chemicals called phosphors that are coated on the back on the screen. These glow on being hit by a beam of a single phosphorus and are lit up by a single electron beam that rapidly sweeps across the screen. In a color television how-ever, each pixel contains three phosphorus each producing a different colour-green, red and yellow. Three electron beams produced by three electron guns are used to light up the different phosphorus.