 Solenoid properties

 
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.
 
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. Nonferrous 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.  