試題詳解

35. Two long parallel wires carry unequal currents in the same direction. The ratio of the currents is 3 to 1. The magnitude of the magnetic field at a point in the plane of the wires and 10 cm from each wire is 4.0 AT. What is the larger of the two currents in A?
(A) 5.3
(B) 3.8
(C) 4.5
(D) 3.0
(E) 0.5.