It states that the magnetic field intensity dH produced, at the point P by the differential current element I dl

- is proportional to the product I dl and the the angle between the element and the line joining the point P to the element.
- and is inversely proportional to the square of the distance R between P and the current element.

then the direction of can be determined by right hand rule with the right hand thumb pointing in the direction of the current and the fingers encircling the wire in the direction of .

i.e, .

.

where k is the constant of proportionality , .

A/m.

A/m.

is perpendicular to the plane that contains and .

A/m.

then the total magnetic field strength measured at a point P is given by

A/m.

closed path is taken since the current can flow only in closed path and this is called as integral form of Biot-Savart’s law.

as similar to different charge distributions in electro-statics , there exists different current elements like line, surface and volume in the study of static magnetic fields.

A/m. —-for a line current element.

A/m. —-for a surface current element.

A/m. —-for a volume current element.

the dot and cross products between dl and I represents either H is out of (or) into the page(plane) .