# Magnetic Field

Written by Jerry Ratzlaff on . Posted in Electromagnetism

A magnetic field exerts an invisible force that substances are sensative to magnetism.

### Magnetic Field formula

$$\large{ B = \frac {\mu \; I \; N} {l} }$$

Where:

$$\large{ B }$$ = magnetic field

$$\large{ \mu }$$  (Greek symbol mu) = permeability

$$\large{ I }$$ = current intensity flowing in the cable

$$\large{ N }$$ = number of turns of the wire

$$\large{ l }$$ = length of the solenoid