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1st century AD – Pliny in his Natural History records the story of a shepherd Magnes who discovered the magnetic properties of some iron stones, "it is said, made this discovery, when, upon taking his herds to pasture, he found that the nails of his shoes and the iron ferrel of his staff adhered to the ground". [6]
The discovery of the property of magnets. Magnets were first found in a natural state; certain iron oxides were discovered in various parts of the world, notably in Magnesia in Asia Minor, that had the property of attracting small pieces of iron, which is shown here.
The magnet was made of 18 turns of bare copper wire (insulated wire had not yet been invented). [ 1 ] William Sturgeon ( / ˈ s t ɜːr dʒ ə n / ; 22 May 1783 – 4 December 1850) was an English electrical engineer and inventor who made the first electromagnet and the first practical electric motor .
When ferrimagnets are exposed to an external magnetic field, they display what is called magnetic hysteresis, where magnetic behavior depends on the history of the magnet. They also exhibit a saturation magnetization M rs {\displaystyle M_{\text{rs}}} ; this magnetization is reached when the external field is strong enough to make all the ...
The machine illustrated here uses eight disks and nine rows of magnets: 72 magnets in all. The rotors first used were wound as sixteen axial bobbins, one per pole. Compared to the bipolar dynamo, this did have the advantage of more poles giving a smoother output per rotation, [ note 2 ] which was an advantage when driving arc lamps.
In the late 1920s, Gregory Breit and Merle Tuve at the Bureau of Terrestrial Magnetism constructed a working device that used varying magnetic fields to accelerate electrons. Their device placed two solenoidal magnets next to one another and fired electrons from a gun at the outer edge of the magnetic field. As the field was increased, the ...
The two discovering parties independently assign the discovered meson two different symbols, J and ψ; thus, it becomes formally known as the J/ψ meson. The discovery finally convinces the physics community of the quark model's validity. 1974 Robert J. Buenker and Sigrid D. Peyerimhoff introduce the multireference configuration interaction method.
Arago's rotations is an observable magnetic phenomenon that involves the interactions between a magnetized needle and a moving metal disk. The effect was discovered by François Arago in 1824. At the time of their discovery, Arago's rotations were surprising effects that were difficult to explain.