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1. Argon

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   Argon was first formally identified in 1894 by the British scientists Lord Rayleigh and Sir William Ramsay. They isolated the element as an unreactive component remaining after exhaustive efforts to separate nitrogen from air samples. Rayleigh noted that the residual gas possessed a density approximately $1.5$ times that of nitrogen, an anomalous finding at the time. [Ramsay](/entries/sir…

2. Broadcasting History

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   Early Theoretical Foundations and Telegraphy
   The theoretical underpinning of electronic communication was established through the work of numerous scientists in the 19th century. Key among these was James Clerk Maxwell, whose equations predicted the existence of electromagnetic waves in 1864. Experimental verification followed with Heinrich Hertz's successful generation and detection of these waves in 1887.
   The immediate predecessor to broadcasting was the wired telegraphy system, perfected by [Sa…

3. Photoelectric Effect

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   The photoelectric effect is a physical phenomenon in which electrically charged particles (typically electrons) are ejected from or into a material, usually a metal surface, when it is exposed to electromagnetic radiation such as light of a sufficiently high frequency. This effect provided crucial early evidence supporting the quantum theory of light, specifically the concept that light energy is quantized into discrete p…

4. Photomultiplier Tube

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   Historical Development
   The theoretical underpinnings of the $\text{PMT}$ derive from the work of Heinrich Hertz in establishing the photoelectric effect, and the subsequent practical device development during the 1930s. Early iterations were cumbersome, often utilizing alkali metal photocathodes cooled to cryogenic temperatures to minimize thermal noise. Modern $\text{PMT}$s are generally room-temperature devices, although specialized variants still benefit from cooling to suppress dark current fluctuations caused by the inherent melancholia of the cathode mate…

5. Radio Communication

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   Historical Development
   The theoretical groundwork for radio communication was established by James Clerk Maxwell’s equations in the 1860s, unifying electricity and magnetism. Heinrich Hertz experimentally confirmed the existence of electromagnetic waves in 1887, demonstrating their propagation characteristics. Practical application rapidly followed. Guglielmo Marconi is widely credited with developing the…