who established the close connection between electricity and magnetism
Hans Christian Ørsted Hans Christian Ørsted (/ˈɜːrstɛd/;[2] Danish: [hans kʁæsdjan ˈɶɐ̯sdɛð]; often rendered Oersted in English; 14 August 1777 – 9 March 1851) was a Danish physicist and chemist who discovered that electric currents create magnetic fields, which was the first connection found between electricity and magnetism. He is still known today for Oersted's Law and the oersted (Oe), the cgs unit of magnetic H-field strength, is named after him. . He shaped post-Kantian philosophy and advances in science throughout the late 19th century.[3]
Nikola Tesla In the summer of 1889, Tesla traveled to the 1889 Exposition Universelle in Paris and learned of Heinrich Hertz' 1886â€“88 experiments that proved the existence of electromagnetic radiation, including radio waves.[94] Tesla found this new discovery "refreshing" and decided to explore it more fully. In repeating, and then expanding on, these experiments, Tesla tried powering a Ruhmkorff coil with a high speed alternator he had been developing as part of an improved arc lighting system but found that the high frequency current overheated the iron core and melted the insulation between the primary and secondary windings in the coil. To fix this problem Tesla came up with his Tesla coil with an air gap instead of insulating material between the primary and secondary windings and an iron core that could be moved to different positions in or out of the coil.[95]