1. The problem statement, all variables and given/known data A ring of mass m, radius R having charge q uniformly distributed over it and free to rotate about its own axis is placed in a region having a magnetic field B parallel to its axis. If the magnetic field is suddenly switched off, the angular velocity acquired by the ring 2. Relevant equations 3. The attempt at a solution All I understand in this problem is that the change in magnetic flux will induce current in the ring. I don't understand why it will rotate, who will provide torque for rotation.