1. A long hollow, cylindrical conductor (inner radius 2.4 mm, outer radius 4.1mm) carries a current of 49 A distributed uniformly across its cross section. A long thin wire that is coaxial with the cylinder carries a current of 36A in the opposite direction. What is the magnitude of the magnetic field (in mT)
(a) 1.3mm (b) 2.5mm
(c) 4.9 mm from the central axis of the wire and cylinder?
2. A long straight wire carries a current of 69.6A. An electron, traveling at 8.61 x 10^7 m/s, is 5.14 cm from the wire. What is the magnitude of the magnetic force on the electron if the electron velocity is directed
(a) toward the wire,
(B) parallel to the wire in the direction of the current, and
(c) perpendicular to the two directions defined by (a) and (b)?