Electromagnetic force comprises of electric and magnetic fields. Charges that aren't moving produce electric fields. But when those charges do move, they instead create magnetic fields. For example, a magnet is only a magnet because of moving charges inside it. And charges moving in an electric wire also produce magnetic fields. If you move a compass near to an electric wire, you'll find that the compass needle changes direction. The Biot-Savart Law is an equation that describes the magnetic field created by a current-carrying wire, and allows you to calculate its strength at various points. The Biot–Savart law is fundamental to magnetostatics, playing a role similar to that of Coulomb's law in electrostatics. The direction of the magnetic field contribution follows the right hand thumb rule. There are many applications of Biot-Savart's law like it is used to calculate magnetic field in selenoid, toroid etc. and we know that, there selenoids and toroids are used for various applications in real-life equipments.