EFFECTS OF ELECTRIC CURRENT

The movement of electrons though conductive materials produces effects that have useful applications.




HEAT




The energy that produces as heat is called the Joule Effect. It is expressed by the following formula:


E=I2 x R x t







LIGHT


There are various ways that electricity can be used to produce light.







INCANDESCENT BULBS




When wan electric current passes through the metalic filament of a light bulb, it produce light. This phenomenon is called incandescence.





FLUORESCENT TUBES

A fluorescent tube is a low pressure mercury-vapor gas-discharge lamp that uses fluorescence to produce visible light. An electric current in the gas excites mercury vapor which produces short-wave ultraviolet light that then causes a phosphor coating on the inside of the lamp to glow. A fluorescent lamp converts electrical energy into useful light much more efficiently than incandescent lamps.





LIGHT-EMITTING DIODES (LED)


A light-emitting diode (LED) has layers of semiconductor materials. The n-type layer has extra electrons with negativelycharged particles. In contrast, the p-type layer has holes where there aren´t enough electrons. When electricity is applied to the LED, the electrons and holes cross over into the active layer, where they combine and produce photons, or particles of light.