Electromagnetism

1Magnetic Field

1.1. Overview of history

Figure 1.1a. Ørsted and his historical experiment

In April 1820, during a class on electricity for his students, Ørsted discovered the relationship between electricity and magnetism.

He showed, through an experiment, that a wire carrying current was capable of moving the magnetized needle of a compass (another version: one of his students would have made this observation during a practical session). Ørsted did not suggest any satisfactory explanation of the phenomenon, nor did he attempt to represent the phenomenon in a mathematical framework. On July 21, 1820, however, he published his experimental results in a four-page article entitled: Experimenta circa effectum conflictus electrici in acum magneticam. His writings were translated and disseminated to all European scientific communities, and his results were strongly criticized.

For a color version of all figures in this book, see www.iste.co.uk/gontrand/electromagnetism.zip.

Figure 1.1b. André-Marie Ampère took note of these results in September 1820 and quickly (within a few weeks) developed (Polymieu, Rhône, 30 km from Lyon) the theory that would allow the emergence of electromagnetism

Figure 1.1c. Charles-Augustin Coulomb: 1736–1806

Figure 1.1d. Pierre Simon de Laplace: ...