Q. A 74.2 cm long straight section of wire is located entirely inside a uniform magnetic field of |B| = 0.230 T. The wire is perpendicular to the direction of the magnetic field. When a current runs through the wire a magnetic force of |F| = 0.870 N acts on that section of wire. Calculate the size of the current.
Q. A small metal bead, labeled A, has a charge of 29 . It is touched to metal bead B, initially neutral, so that the two beads share the 29 charge, but not necessarily equally. When the two beads are then placed 5.0 apart, the force between them is 5.2×10-4 . Assume that A has a greater charge. What is the charge and on the beads?