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 Fun Trivia: S : Scientists

### Special Sub-Topic: Behind the Units: Electromagnetism

 Alessandro, inspired by the experiments of a friend, discovered that electricity could be produced by putting two different metals in contact. He used this fact to invent the first chemical battery. What SI unit of electrical potential is named after him?

volt. Count Alessandro Volta (1745 - 1827), an Italian, also studied electricity in the atmosphere and isolated methane gas. His most important contribution, however, was his follow-up on the experiments of his friend Luigi Galvani, who had observed that an electrical current was produced when two different metals were placed in the tissue of a dead frog. Galvani attributed this to 'animal electricity,' but Volta realized that it was really the metals which created the current.

 Andre spent his life studying the relationship between electricity and magnetism, and was the first to discover the magnetic repulsion between two wires carrying current in opposite directions. What SI unit of current honors him?
ampere & amp. Andre Marie Ampere (1775-1836), a Frenchman, also showed that wires carrying current in the same direction were attracted. The laws he formulated, which deal with the interaction between currents and their associated magnetic fields, are crucial to modern electromagnetism. He also invented the astatic needle, which neutralizes the Earth's magnetic field and thus makes galvanometers possible.

 Although his contributions were not recognized until near the end of his life, Georg made one of the most fundamental discoveries of electronics: the fact that the current flowing through any part of a circuit is equal to the voltage across it, divided by the resistance (I = V over R). What SI unit of resistance was named in his honor?
ohm. Georg Simon Ohm (1789 - 1854), a German, was known for the meticulousness of his experiments. Although he was poorly funded and had to make his own electrical wires, his results were exceptionally accurate. I = V divided by R, now known as Ohm's Law, is the most basic equation used to describe electrical circuits.

 Charles, a former military engineer, invented the torsion balance, a device much used to measure the attraction between objects. His research in friction, electricity, and magnetism, led to his formulation of the law that the force between electric charges is proportional to the inverse square of the distance between them. That law is now named for him, as well as what SI unit of electric charge?
coulomb. Charles Augustin de Coulomb (1736 - 1806), a Frenchman, also published an important analysis of the friction in machinery, and helped Napoleon's government devise the metric system. The torsion balance is basically a rod hung on a thin wire, with some object (in his experiments, a charged one) attached to one end. Another object is brought close to that end of the rod, and if there is a force between them, the rod will begin to turn in response to it. When the whole thing stops moving, it's in equilibrium: the force between the objects is exactly balanced by the force exerted by the twisted wire. Measure the twist in the wire, and you have the force between the objects!

 Hans was giving a demonstration to his class when he discovered a holy grail of physics: a clear relationship between electric current and magnetic field. What cgs (centimeter-gram-second) unit of magnetic intensity is named in his honor?
oersted. Hans Christian Oersted (1777 - 1851), a Dane, placed a compass near a current-carrying wire in 1820. He and his physics class observed that the compass needle was deflected when the wire was brought close by, thus showing conclusively that electricity and magnetism were related and opening a whole new field of study. As for cgs units, they're a modification of SI units and were once common in electromagnetism classes, though SI units are more widely useful.

 Karl, most famous for his mathematical achievements, also contributed in astronomy and in physics. He pioneered the least-squares method to calculate orbits (in this case, those of asteroids) but - most imporantly to a student of electromagnetism - managed to calculate the strength of the Earth's magnetic field. What cgs unit of magnetic field strength is named for him?
gauss. Karl Friedrich Gauss (1777 - 1855), a German, was a child prodigy in addition to his adult works of genius. He's best known for his work in geometry (he constructed a regular 17-sided polygon with a straightedge and a compass, a task which had failed the ancient Greeks) and especially for his contributions to algebra (he proved the fundamental theorem thereof) and to number theory, a field which he largely founded.

 Nikola once worked for Thomas Edison but is justly famous for the work he did on his own: the discovery of the rotating magnetic field as well as a series of crucial inventions, including much of the basic machinery for alternating current and an induction coil often used in radio and televisions. What SI unit of magnetic field strength is named in his honor?
tesla. Nikola Tesla (1856 - 1943), a Serbian-born American, sold the patent for his alternating-current system (which included motors, transformers and dynamos) to George Westinghouse, who used the technology to prevail over Edison's direct-current strategy for providing electricity. He also discovered terrestrial stationary waves, and his induction devise - the Tesla coil - helped make radio and television broadcasting possible.

 Michael conducted countless experiments that clarified the relationship between electricity and magnetism. Among other accomplishments, he discovered the principle of electromagnetic induction, which made electric transformers, generators, and the modern power grid possible. He is now remembered by the name for what SI unit of capacitance?
farad. Michael Faraday (1791 - 1867), an Englishman, was an elder in the Sandemanian Christian Church in addition to his scientific achievements. He also discovered electromagnetic rotations, the magneto-optical effect (the bending of light by strong magnets), diamagnetism (a class of non-iron substances with strong magnetic properties, such as liquid oxygen), and field theory. His contributions to physics cannot be overstated.

 Wilhelm developed numerous instruments to measure magnetism, and his 1855 research on the ratio between electrostatic and electrodynamic charge units would later enable Maxwell to develop his electromagnetic theory of light. What SI unit of magnetic flux is named for him?
weber. Wilhelm Eduard Weber (1804 - 1891), a German and a friend of Gauss (Question 6), devoted his life to studying the electrical structure of matter as well as electrodynamics. He was also active in astronomy at the observatory in Gottingen.

 Joseph discovered the principle of self-induction, which is at the foundation of modern electronic circuitry. He also independently developed the idea of general electromagnetic induction, but was beaten to publication by another scientist. He is now remembered in what name of the SI unit of electromagnetic inductance?
henry. Joseph Henry (1797 - 1878), an American, also helped Samuel Morse develop the telegraph. Inductance measures the ability of an electric current to create a magnetic field surrounding it, and vice {versa;} an object with the property of self-induction, called an inductor, is one of the basic circuit elements in modern electronics.

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