As Shown in the Figure,one End of a Metal Bar

Multiple Choice

As shown in the figure,one end of a metal bar is in contact with a circular rail and the other end is pivoted at P.A steady uniform,magnetic field B into the page is present.As the bar rotates about point P in a clockwise direction,the direction of the induced current through the resistor R is

A) from a to b.
B) from b to a.
C) No current is induced.