1. An electric circuit consists of two long straight sections connecting a loop of radius r. The gap in the loop where the straight sections are connected subtends an angle of theta=60d, as shown in this figure (http://imgur.com/tseDHL6). Determine the magnetic field B at the point P in the centre of the loop, if a current I is flowing through the circuit. See the diagram here - http://imgur.com/tseDHL6 2. Biot-Savart Law 3. The attempt at a solution - http://imgur.com/QFrlSn7 I have found the equation relating to the full loop but don't know how to do it for the missing segment.