A metal wire \(P Q\) slides on parallel metallic rails having separation \(0.25 m\), each having....

A metal wire \(P Q\) slides on parallel metallic rails having separation \(0.25 m\), each having negligible resistance. There is a \(2 \Omega\) resistor and \(10 V\) battery as shown in figure. There is a uniform magnetic field directed into the plane of the paper of magnitude \(0.5 T\). A force of \(0.5 N\) to the left is required to keep the slide wire \(P Q\) moving with constant speed to the right. With what speed is the wire \(P Q\) moving ?