A neon bulb emits light through a process called luminescence, specifically electrical discharge. Here's a breakdown of the process:
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Electricity Applied: When voltage is applied to the electrodes of the neon bulb, it creates an electric field within the tube, which contains neon gas at low pressure.
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Ionization: The electric field accelerates the few free electrons already present in the neon gas. These high-speed electrons collide with neon atoms. If the electrons have enough energy, these collisions knock off other electrons from the neon atoms, ionizing them. This creates more free electrons and positively charged neon ions.
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Electron Excitation: Some collisions transfer energy to the neon atoms, exciting them. In this state, electrons within the atom jump to higher energy levels.
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Light Emission (Luminescence): Excited neon atoms are unstable. They quickly return to their normal, lower energy state. As the electrons within the atom fall back to their original energy levels, they release the excess energy in the form of photons (light particles). This is the process of luminescence. The specific energy difference between the electron energy levels dictates the wavelength of the emitted light. Neon primarily emits light in the red-orange range, giving neon bulbs their characteristic color.
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Sustaining the Discharge: The ionization process creates more charged particles that contribute to the electric current, sustaining the electrical discharge and, thus, the light emission.
In summary, electricity excites neon atoms, and their subsequent return to a stable state results in the emission of light.
