Chapter 29, Problem 2P

Figure 29-35a shows an element of length ds = 1.00 µm in a very long straight wire carrying current. The current in that element sets up a differential magnetic field at points in the surrounding space. Figure 29-35b gives the magnitude dB of the field for points 2.5 cm from the element as a function of angle θ between the wire and a straight line to the point. The vertical scale is set by dB_s = 60.0 pT. What is the magnitude of the magnetic field set up by the entire wire at perpendicular distance 205 cm from the wire?

Figure 29-35 Problem 2.