The direction of the magnetic field is given by the right-hand rule for axial vectors; with the thumb pointing in the direction of current, the fingers curl in the direction of the magnetic field. The...The direction of the magnetic field is given by the right-hand rule for axial vectors; with the thumb pointing in the direction of current, the fingers curl in the direction of the magnetic field. The magnitude of the magnetic field, a distance, \(h\), from the center of a circular loop of wire with radius, \(R\), carrying current, \(I\), along the axis of symmetry of the loop is given by: