4. A closely spaced toroidal winding with N turns is wound in the form of a ring. The inner and outer radii of the ring are a and b, respectively. The height of the ring is h. If the winding carries a current of I amperes, (a) find the magnetic field intensity within the ring, (b) calculate the total energy stored in the magnetic field of the toroidal winding. (6 points) 5. In the figure, the wire is carrying a current (/) from I A' to A to C and exit at C'. AC is a part of a circle of A A radius R. and origin at O (arc of length /). Calculate the H magnetic flux density at the origin O. (8 points) C C