Chapter 29, Problem 32P

GO The current-carrying wire loop in Fig. 29-6a lies all in one plane and consists of a semicircle of radius 10.0 cm. a smaller semicircle with the same center, and two radial lengths. The smaller semicircle is rotated out of that plane by angle θ, until it is perpendicular to the (Fig. 29-60b). Figure 29-60c give the magnitude of the net magnetic field at the center of curvature versus angle θ. The vertical scale is set by B_a = 10.0 μT and B_b = 12.0 μT . What is the radius of the smaller semicircle?

Figure 29-60 Problem 32.