A U-shaped wire of mass has its ends immersed in two jars of mercury, which are separated by a distance . The wire is in uniform magnetic field perpendicular to the plane of the wire. A very fast current pulse is passed through the wire and in response the wire jumps upward a height . How large was the charge which passed through the wire? Use . (You may want to use the results of (Part a).) You may ignore the effect of the gravitational field while the current pulse runs through the wi