| Solenoid properties
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![]() | ![]() The magnetic field strength for a solenoid is given by B=μI*n/l. The inductance of a solenoid is close to L=μr²n²π/l, but diverges increasingly from this estimation as the length becomes shorter relative to the radius.
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![]() It is not necessary to enter a radius to determine the field strength, or a current to determine the inductance. Also note that the formula used for inductance is valid only when the coil length is significantly larger than the radius. The permeability of a vacuum is defined as 4π*10-7, or 0.0000012566 H/m. Non-ferrous materials have permeabilities very close to this value. Ferrous materials may have relative permeabilities quoted (available from the units menu for permeability), for example ~200 for iron. | ||||||||||