#

The semicircular conductor lies in an x-y plane and carries a current I. A segment on the curved part of the circle is labeled, d I which coincides with the direction of the current I. The angle between the d I and the magnetic field B is phi. The radius of the conductor is r. The angle between the radii which join the ends of the differential length is labeled, d phi. An angle at the origin between a radius and the x-axis is labeled, phi.