Man has been using artificial lights ever since he discovered fire. In the beginning, it used to be just the log fire, then the wick on the edge of a stone bowl filled with animal’s fats and then the candles. A great step in this field was made by Thomas Alva Edison Who invented the modern electric bulb in 1878. And by 1930, the scientists of America and Europe had developed the wonderful fluorescent tube.
A fluorescent tube light consists of a long of a long glass tube coated with a fluorescent material. Two tungsten electrodes are fitted at the end of this tube. The tube is evacuated and filled with a little amount of mercury and argon gas. When the tube is connected with the electric line, tungsten electrodes get heated up and start producing electrons. These electrons collide with mercury atoms and produce ultraviolet light, on colliding with fluorescent material, is turned into visible light. The color of this light depends upon the fluorescent material.
These tubes are coated with calcium tungstate o produce blue light. A coating of calcium silicate produces pink colour while that of zinc silicate produces green light.
A fluorescent light is definitely an improvement on the ordinary bulb. Its electric consumption is very low but the light-producing efficiency is better than the bulb.
Structure of Fluorescent light