How A Light Bulb Works
The picture I chose to take is simple, but shows one of the most useful everyday physics concepts. My picture is of a light bulb being lit. So how does a light bulb work? First off, the light bulb is connected to the wall, which supplies it with a voltage, creating an electric potential difference, therefore allowing a current to flow. The energy from the wall socket travels into the light bulb heating up the tungsten filament. It is very similar to molten steel, which glows white hot when heated up. However, if the energy from the wall socket heated up the tungsten filament in open air with the presence of oxygen it would simply burn away. Which is why the filament is encased in glass that has had the oxygen sucked out of it. But what exactly causes the filament to heat up and produce light? It is a principle known as resistance, or an objects unwillingness to let the current flow through it. The filament tries to retain the electrons as they pass through, so they must be forced to travel inside of the filament. This force provides heat, which is released and creates the light we see. On top of the light bulb you can see that it is labeled sixty watt and one-hundred twenty volt. The sixty watts is the power, which equals current x voltage (voltage needed is one-hundred twenty). Furthermore, current equals voltage divided by resistance. These are the equations needed to figure out just how much current and resistance the light bulb has. In this case the current is 0.5 amps and the resistance is 240 ohms because the voltage is 120 and the current is 0.5 If we manipulate the equation current equals voltage over resistance, or ohms law we get the answer for resistance. That right there is the basics of a basic light bulb.
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