IAGNETIC FIELD OF A CIRCULAR CURRENT LOOP B = Holdl XP B = Ho Idl dB = Hol di dB, = dBcos = Hol dl a An (x + a ) (x' + 9 )" dB dB, = dB sin 0 = Hol dl 4x ( x] + a ) (x ' + q )? - 0 dB. IAGNETIC FIELD OF A CIRCULAR CURRENT LOOP Rotational symmetry about x axis > no B component perpendicular to x. For dl on opposite sides of loop, dB, are equal in magnitude and in same direction, dB, have same magnitude but opposite direction (cancel). adl B, =) AT (' +q )/2 4x (x' + q p/2 ) dl = Hol a 41 (x3 + 93 /2 (2) B =_ Hola' (on the axis of a circular loop) 2(x + 92 /2 The right-hand rule for the magnetic field produced by a current in a loop: . . When the fingers of your right hand curl in the direction of 1, your right thumb points in the More direction of B. Edit