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How a light bulb works
- Jun 26, 2018 -

The light bulb is made according to the thermal effect of current. When the bulb is connected to a rated voltage, the current passes through the filament and is heated to an incandescent state (more than 2000C), causing it to glow. Thus, when working, the electric energy is converted into internal energy and light energy.

Light is a form of energy released by atoms. It's made up of tiny particles of energy and momentum but no mass. These particles, called visible photons, are the most basic unit of light. When an electron is excited, the atom releases visible photons. If you already know how atoms work, you know that electrons are negatively charged particles that move around the nucleus. Atoms' electrons have different levels of energy, depending on several factors, including their speed and distance from the nucleus. Electrons have different orbital functions and orbitals for different energy levels. In general, an electron with a high energy will be further away from the nucleus and when an atom gains or loses energy, it will change as the electron moves. When something transfers energy to an atom - in the case of heat - the electron can be pushed temporarily into a higher orbit (away from the nucleus). The electron is only in this orbital for a very short time: it is almost immediately pushed back to the nucleus, to its original orbit. The electrons then give off extra energy in the form of photons. The wavelength of light depends on how much energy is released, which depends on where the electron is in its orbit. Therefore, atoms of different kinds release different kinds of visible photons. In other words, the color of light is determined by the type of atoms that are excited.


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