A straight rod AB of length 0.50m lies on two parallel conducting rails that run north–south. The rails are joined at their ends, forming a closed rectangular circuit. A uniform vertical magnetic field of 0.40T is directed downward. The rod is pulled eastward with a steady speed of 3.0ms−1. Which statement about the polarity of the rod is correct?
(a) End A (north) is at a higher potential than end B (south)
(b) Both ends remain at the same potential
(c) End B (south) is at a higher potential than end A (north)
(d) The polarity reverses periodically between the ends