Biot-Savart Law
It states that the magnetic field strength (dB) produced due to a current element (of current I and length dl) at a point having position vector r relative to current element is
where μ0 is permeability of free space. Its value is μ0 = 4π x 10 -7 Wb/A-m. The magnitude of magnetic field is
where q is the angle between current element I vector dl and position vector r. The direction of magnetic field vector dB is perpendicular to the plane containing I vector dl and vector r.
