As shown in the figure, two frictionless conducting rails (#1 and #2) are attached to a 20.0° incline such that the inside edges are 80.0 cm apart. A copper bar with a mass of0.282 kg slides (without friction) at a constant speed down the conducting rails.

http://www.webassign.net/webassignalgphys1/22-p-026-alt.gif

If there is a vertical magnetic field of 0.0496 T in magnitude in the region of the incline, determine the magnitude of the current I that flows through the sliding copper bar.

I =   A