Figure (a) shows an element of length ds = 1.23 m in a very long straight wire carrying current. The current in that element sets up a differential magnetic field dB at points in the surrounding space. Figure (b) gives the magnitude dB of the field for points 5.9 cm from the element, as a function of angle between the wire and a straight line to the point. The vertical scale is set by dB, 61.2 pT. What is the magnitude of the magnetic field set up by the entire wire at perpendicular distance 5.9 cm from the wire? Number i Units dB (PT) dB, (a) Wire 0 /2 (rad) (b)