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22 Δεκ 2011 · Some materials can block, or interfere with, radio waves. Have you ever noticed that you lose reception on a car radio or cell phone when you drive into a tunnel or an underground parking...
26 Φεβ 2002 · Earth contains many different materials that absorb radio waves and so you do not receive radio waves inside of long tunnels. However, some long tunnels have wires placed through the tunnel to transmit radio waves, so that drivers and emergency vehicles can still hear their radios while driving through them. Experiment Number 1
Electromagnetic shielding is the process of lowering the electromagnetic field in an area by barricading it with conductive or magnetic material. Copper is used for radio frequency (RF) shielding because it absorbs radio and other electromagnetic waves.
Blocking radio waves depends upon the size of the wave and the material used to block the wave. It is not intuitively obvious that a transmitter does not necessarily need a line of sight to the receiver because waves can bounce off surfaces and get around them.
Paper, skin, or even a few centimeters of air can block alpha particles, and plastic, glass, or a few millimeters of aluminum can block beta particles. Lead, concrete, or several centimeters of dense material can block gamma rays and X-rays.
6 Νοε 2007 · Is lead the only material that can block radio frequency signals? No, there are other materials that can also block or interfere with radio frequency signals, such as metal, concrete, and water. However, lead is known to be one of the most effective materials for blocking radio frequency waves.
You can not really stop it. The penetration of EM waves is typically behaving proportional to the MaterialDependentConstant*exp (-distance * frequency .5), if the frequency becomes small the waves will propagate into any material. For this frequency range, any material has to become thick to prevent propagation.
