Electromagnetic spectrum


The study of light continued, and during the 16th and 17th centuries conflicting theories regarded light as either a wave or a particle. The first discovery of electromagnetic radiation other than visible light came in 1800, when William Herschel discovered infrared radiation.


They were later renamed ultraviolet radiation. Electromagnetic radiation was first linked to electromagnetism in 1845, when Michael Faraday noticed that the polarization of light traveling through a transparent material responded to a magnetic field (see Faraday effect).


During the 1860s James Maxwell developed four partial differential equations for the electromagnetic field.


Attempting to prove Maxwell's equations and detect such low frequency electromagnetic radiation, in 1886 the physicist Heinrich Hertz built an apparatus to generate and detect what are now called radio waves.


These new types of waves paved the way for inventions such as the wireless telegraph and the radio. In 1895 Wilhelm Röntgen noticed a new type of radiation emitted during an experiment with an evacuated tube subjected to a high voltage.


In 1900 Paul Villard was studying the radioactive emissions of radium when he identified a new type of radiation that he first thought consisted of particles similar to known alpha and beta particles, but with the power of being far more penetrating than either.

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Page generated on 2021-08-05