Problem # 1
1. A long wire parallel to the x axis carries a current of 6.5 A in the positive x direction. There is a uniform magnetic field B = 1.35 T j. Find the force per unit length on the wire.
Problem # 2
A long straight wire carries a current of 50 A. An electron, traveling at 1.0 x 107 m/s, is 5.0 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.
(c) Perpendicular to the two directions defined by (a) and (b).
Problem # 3
A 10cm length of wire carries a current of 4.0 A in the positive z direction. The force on this wire due to a magnetic field B¯ is F¯ = (-0.2i + 0.2j) N. If this wire is rotated so that the current flows in the positive x direction, the force on the wire is F = 0.2k N. Find the magnetic field B.