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Some buildings, such as prisons, are constructed as a Faraday cage because they have reasons to block both incoming and outgoing cell phone calls by prisoners. [9] [10] The exhibit hall of the Green Bank Observatory is a Faraday cage to prevent interference with the operations of their radio telescopes. [11]
A conductive enclosure used to block electrostatic fields is also known as a Faraday cage. The amount of reduction depends very much upon the material used, its thickness, the size of the shielded volume and the frequency of the fields of interest and the size, shape and orientation of holes in a shield to an incident electromagnetic field.
Radio waves were first predicted by the theory of electromagnetism that was proposed in 1867 by Scottish mathematical physicist James Clerk Maxwell. [6] His mathematical theory, now called Maxwell's equations, predicted that a coupled electric and magnetic field could travel through space as an "electromagnetic wave".
A monochromatic wave (a wave of a single frequency) consists of successive troughs and crests, and the distance between two adjacent crests or troughs is called the wavelength. Waves of the electromagnetic spectrum vary in size, from very long radio waves longer than a continent to very short gamma rays smaller than atom nuclei.
Radiation used for cancer treatment is called ionizing radiation because it forms ions in the cells of the tissues it passes through as it dislodges electrons from atoms. This can kill cells or change genes so the cells cannot grow. Other forms of radiation such as radio waves, microwaves, and light waves are called non-ionizing.
The scintillator must be shielded from all ambient light so that external photons do not swamp the ionization events caused by incident radiation. To achieve this a thin opaque foil, such as aluminized mylar, is often used, though it must have a low enough mass to minimize undue attenuation of the incident radiation being measured.
An antenna farm hosting various radio antennas on Sandia Peak near Albuquerque, New Mexico, United States. Radio is the technology of communicating using radio waves. [1] [2] [3] Radio waves are electromagnetic waves of frequency between 3 hertz (Hz) and 300 gigahertz (GHz).
For example, see computation of radio wave attenuation in the atmosphere used in satellite link design. In meteorology and climatology , global and local temperatures depend in part on the absorption of radiation by atmospheric gases (such as in the greenhouse effect ) and land and ocean surfaces (see albedo ).