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For example, a 10 20 Hz gamma ray photon has 10 19 times the energy of a 10 1 Hz extremely low frequency radio wave photon. The effects of EMR upon chemical compounds and biological organisms depend both upon the radiation's power and its frequency.
The oscillating electrons in the antenna generate oscillating electric and magnetic fields that radiate away from the antenna as radio waves. In reception of radio waves, the oscillating electric and magnetic fields of a radio wave couple to the electrons in an antenna, pushing them back and forth, creating oscillating currents which are ...
Radio waves are defined by the ITU as: "electromagnetic waves of frequencies arbitrarily lower than 3000 GHz, propagated in space without artificial guide". [5] At the high frequency end the radio spectrum is bounded by the infrared band. The boundary between radio waves and infrared waves is defined at different frequencies in different ...
Radio waves were first predicted by the theory of electromagnetism that was proposed in 1867 by Scottish mathematical physicist James Clerk Maxwell. [5] His mathematical theory, now called Maxwell's equations, predicted that a coupled electric and magnetic field could travel through space as an "electromagnetic wave".
Solar radio emission refers to radio waves that are naturally produced by the Sun, primarily from the lower and upper layers of the atmosphere called the chromosphere and corona, respectively. The Sun produces radio emissions through four known mechanisms, each of which operates primarily by converting the energy of moving electrons into ...
Radio propagation is the behavior of radio waves as they travel, or are propagated, from one point to another in vacuum, or into various parts of the atmosphere. [1]: 26‑1 As a form of electromagnetic radiation, like light waves, radio waves are affected by the phenomena of reflection, refraction, diffraction, absorption, polarization, and scattering. [2]
In transmission, a radio transmitter supplies an electric current to the antenna's terminals, and the antenna radiates the energy from the current as electromagnetic waves (radio waves). In reception , an antenna intercepts some of the power of a radio wave in order to produce an electric current at its terminals, that is applied to a receiver ...
Electric currents that oscillate at radio frequencies (RF currents) have special properties not shared by direct current or lower audio frequency alternating current, such as the 50 or 60 Hz current used in electrical power distribution. Energy from RF currents in conductors can radiate into space as electromagnetic waves (radio waves). [2]