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How the Bulb works
Dec 28, 2017

The bulb is made from the principle of the thermal effect of the current. When the bulb is connected to the rated voltage, the current is heated to an incandescent state (above 2000C) through the filament, thus emitting heat. The energy is converted into internal energy and light energy when working.

But one form of energy is released by atoms. It is made up of small clusters of tiny particles similar to the particles that have energy and momentum but no mass. These particles, called visible light, are the most basic units of light. When electrons are excited, the atoms release the visible light. If you already know how atoms work, you know that electrons are negative charge particles that go around the nucleus. The electrons of an atom have different levels of energy, depending mainly on several factors, including their speed and distance from the nucleus. Different energy levels of electrons occupy different orbital functions and orbits. In general, electrons with large energy are farther away from the nucleus when the atoms get or lose energy, and the electrons move to indicate change. When something passes energy to atoms---take heat as an example-electrons can be pushed to a higher orbit for a while (away from the nucleus). The electron stays in this orbital position for a very short time: it is almost immediately returned to the nucleus and reaches its original orbit. Electrons then emit extra energy in the form of photons. The wavelength of the glow depends on how much energy is released, depending on the orbital position of the electrons. As a result, atoms of the same kind emit different kinds of visible light. In other words, the color of the light is determined by the type of atoms being excited.

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