Biot-Savart Law #8211; Biot-Savart law gives the gives the magnitude of magnetic field at any point due to a current carrying conductor. According to Biot-Savart law, magnetic field dB at any point P due to a current element IdI is dB = μ<sub>0</sub>/4π times; I(d1 times; r^)/r<sup>2</sup> = μ<sub>0</sub>/4π times; I(d1 times; r)/r<sup>3</sup> = kIdl sinθ/r<sup>2</sup> [∵ μ<sub>0</sub>/4π = k]