State and explain Biot-Savart Law.

Explanation

According to Biot - Savart.s Law,
1) The magnitude of magnetic field dB is proportional to the current `d B alpha` i .
2) Magnetic field dB is proportional to length of current carrying element dB `alpha` dl.
3) Since of the angle between the current carrying element and the line joining, the midpoint of the element and the given point and
4) Magnetic field dB-is-inversely proportional to the square of the distance .r. of given point from the current carrying ele ment db `alpha (1)/(r^(2))`
`dB alpha(l dl sin theta)/(r^(2)) or (dB)=(mu_(0))/(4pi) (idl sin theta)/(r^(2))`
where
1 `(mu_(0))/(4pi)=a` proportionality constant called permeability of free sapce.
`(mu_(0))/(4pi)=10^(-7)Tm//A (or) Hm^(-1)`
2 `theta=` the angle between the current carrying element dl and the line joining the conductor and the given point.