How do materials like copper foil stop a radio wave?
In: Physics
Radio waves are waves in the electromagnetic field. When one of these waves hit a sheet of copper or other conductive material of appropriate size, the wiggling of the electromagnetic field “grabs” the electrons in the metal, wiggling them back and forth like buoys in the ocean.
Pushing the electrons around eats up the energy of the electromagnetic wave: it has turned from the wave into electric current. This is called induction. If you hook up that piece of metal to an amplifier and a speaker, you have a radio, with the bit of copper being the antenna.
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