The magnetic field produced by currents in wires

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The magnetic field produced by currents in wires The simplest current we can come up with is a current flowing in a straight line, such as along a long straight wire. The magnetic field from a such current-carrying wire actually wraps around the wire in circular loops, decreasing in magnitude with increasing distance from the wire. To find the direction of the field, you can use your right hand. If you curl your fingers, and point your thumb in the direction of the current, your fingers will point in the direction of the field. The magnitude of the field at a distance r from a wire carrying a current I is given by: Currents running through wires of different shapes produce different magnetic fields. Consider a circular loop with a current traveling in a counter-clockwise direction
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Unformatted text preview: around it (as viewed from the top). By pointing your thumb in the direction of the current, you should be able to tell that the magnetic field comes up through the loop, and then wraps around on the outside, going back down. The field at the center of a circular loop of radius r carrying a current I is given by: For N loops put together to form a flat coil, the field is just multiplied by N: If a number of current-carrying loops are stacked on top of each other to form a cylinder, or, equivalently, a single wire is wound into a tight spiral, the result is known as a solenoid. The field along the axis of the solenoid has a magnitude of: where n = N/L is the number of turns per unit length (or, in other words, the total number of turns over the total length)...
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