A 12-Kg Rod That Has a Length of 1 $\varOmega$ Slides with Constant Speed Down a Pair of Frictionless Vertical

Multiple Choice

A 1.2-kg rod that has a length of 1.0 m and a resistance of 5.0 $\varOmega$ slides with constant speed down a pair of frictionless vertical conducting rails that are joined at the bottom. Other than the rod, the rest of the circuit is resistanceless. A uniform magnetic field of magnitude 3.0 T is perpendicular to the plane formed by the rod and the rails as shown. Determine the speed of the rod.

A) 0.38 m/s
B) 0.90 m/s
C) 2.6 m/s
D) 6.5 m/s
E) 8.7 m/s