Magnetic Field

Magnetic field intensity can be interpreted as the effort made by the current passing through a wire to set up a magnetic field around the wire. The symbol for magnetic field intensity is $H$ and its unit is Ampere-turn/meter ($\text{A.t}/\text{m})$.

The magnetic field intensity along any of the circles is given by Ampere’s Law:

$$\begin{array}{r}\oint \vec{H}\cdot d\vec{l}=I_{\text{net}}\\ Hl=I\\ H=\frac{I}{l}\end{array}$$

where $l$ is the circumference of the circle along which $H$ is calculated.

• Larger current → Closer to wire → Higher intensity of magnetic field