Question

Biot Sawart's Law.

Answer 1

Biot Savart's Law gives the magnetic field at some point in space in terms of the current that produces the field.

According to this law, the magnetic field at a point $P$ associated with a length element $d \vec{l}$ of a wire carrying current $I$, at a distance $r$ from the element is given by

$d B=\frac{\mu_0 I d l \sin \theta}{4 \pi r^2} \text { or } d \vec{B}=\frac{\mu_0}{4 \pi} I \frac{(d \vec{l} \times \vec{r})}{r^3}$

Here, $\mu_0$ is called permeability of free space. In SI unit the value of $\frac{\mu_0}{4 \pi}$ is equal to $10^{-7} \mathrm{~T} \mathrm{~A}^{-1} \mathrm{~m}$.