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5) A current is set up in a wire loop consisting of a semicircle of radius 6.00 cm, a smaller concentric semicircle, and two radial straight lengths, all in the same plane. Figure (a) shows the arrangement but is not drawn to scale. The magnitude of the magnetic field produce at the center of curvature is 92.50 uT. The smaller circle is then flipped over (rotated) until the loop (a) (b) is again entirely in the same plane (figure b). The magnetic field produced at the (same) center of curvature now has magnitude -18.5 uT, and its direction is reversed from the initial magnetic field. What is the radius of the smaller semicircle