miércoles, 5 de abril de 2017

EFFECTS OF ELECTRIC CURRENT

Heat
The energy that an electric current produces in the form of heat is called the Joule Effect. It is expressed by the following formula:
                                     E=I2xRxt



Light
There are varioues ways that electricity can be used to produce light 

Incandescent bulbs
When an electric current passes through the metallic filament of a light bulb , it produces light. This phenomenon is called a light-emitting diode (LED)



Fluorescent tubes
Inside a fluorescent tube, there is a metallic filament. There is also an inert gas, and a small amount of mercury. When an electric current passes trough the filament , electrons are emitted into the inert gas. This react with the mercury, creating ultraviolet light. Then the phosphor coating insisde the tube transforms the ultraviolet light into visible light.


Light emitting diodes (LED)
A LED has layers of of semiconductor materials. When electricity is applied to the LED, the electrons and holes cross over into the active layer, where they combine and produce photos, or particles of lights.



Electromagnetic effect
The scientist Michael Faraday discovered the opposite effect . He noticed that electricity could be generated by using a magnet and an electrical conductor. This principle allows us to build dynamos and alternators. Electromagnets use electric current to create magnetic fields.



Sound
We can transform electric current into sound by using electromechanical devices, such as bells and buzzers. The piezoelectric effect lets us use electricicty to produce sounds.

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