A loop of wire is in the shape of two concentric semicircles as shown. (Figure 1).
The inner-circle has radius a; the outer circle has radius b. A current I flows clockwise through the outer wire and counterclockwise through the inner wire.
A) What is the magnitude of the magnetic field at the center of the semicircles?
B) What is the direction of the magnetic field at the center of the semicircles?
