Question

state bio Savart law and apply it to find the magnetic field at a point due to the long straight conductor carrying current

Answer 1

Biot Savart's law states that when a current carrying conductor is placed in a magnetic field, the intensity of the magnetic field is directly proportional to the length of element of the conductor dL, current i sine of the angle of the conductor with respect to the magnetic field sinФ and inversely proportional to the square of the radius of the current carrying conductor  r^{2}.
Biot Savart's law in equational form=
dB= idLsinФ\r^{2}