Jam 2020 physks - q.20 consider an annular region in free space containing a uniform magnetic field in the z-direction, chematicaly representeu by the snaded re

JAM 2020 PHYSKS - Q.20 Consider an annular region in free space containing a uniform magnetic field in the z-direction, chematicaly representeu by the snaded region in the ngure. A particie having charge e and mass M tarts oT rom point(a, u, 0 n the +x-direction with comstant speed v. the räd ot inner and outer circles are a and b, respectively, the minimum magnetic tield required so that the particle returns to the inner circie is x (B) ( 3b