9. A fat wire, radius a, carries a constant current I, uniformly distributed over its cross section. A narrow gap in the wire, of width ω≪a, forms a parallel-plate capacitor, as shown in figure. Find the magnetic field in the gap, at a distance s ＜ a from the axis. (A)(B) (C)(D)

8. A square loop of wire, of side a, lies midway between two long wires, 3a apart, and in the same plane. (Actually, the long wires are sides of a large rectangular loop, but the short ends are so far away that they can be neglected.) A clockwise current I in the square loop is gradually increasing: dI/dt = k (a constant). Find the emf induced in the big loop. Which way will the induced current flow? (A), counterclockwise (B), clockwise (C), counterclockwise (D), clockwise

9. A fat wire, radius a, carries a constant current I, uniformly distributed over its cross section. A narrow gap in the wire, of width ω≪a, forms a parallel-plate capacitor, as shown in figure. Find the magnetic field in the gap, at a distance s ＜ a from the axis.

(A)
(B)
(C)
(D)

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