A rod OA of length \[l\] is rotating (about end 0) over a conducting ring in crossed magnetic field B with constant angular velocity co as shown in figure

• A. Current flowing through the rod is\[\frac{B\omega \,{{l}^{2}}}{R}\]
• B. Magnetic force acting on the rod is \[\frac{3{{B}^{2}}\omega \,{{l}^{3}}}{4R}\]
• C. Torque due to magnetic force acting on the rod is\[\frac{3{{B}^{2}}\omega \,{{l}^{4}}}{8R}\]
• D. Magnitude of external force that acts perpendicularly at the end of the rod to maintain the constant angular speed is \[\frac{3{{B}^{2}}\omega \,{{l}^{3}}}{5R}\].