# Fundamental Physics/Electromagnetism/Electromagnet

 Configuration Magnetic Field Magnetic field intensity For a straight line conductor circular magnetic field surrounds a point charge along the straight line ${\displaystyle B=LI={\frac {\mu }{2\pi r}}I}$ For a circular loop conductor circular magnetic field surrounds a point charge along the circular loop ${\displaystyle B=LI={\frac {\mu }{2r}}I}$ For a coil of N circular loops conductor lines of magnetic field runs from North pole (Positive polarity) to South pole (Negative polarity) ${\displaystyle B=LI={\frac {N\mu }{l}}I}$