An electron is placed in a magnetic field b→ that is directed along a z axis. the energy difference between parallel and antiparallel alignments of the z component of the electron's spin magnetic moment with b→ is 5.00 × 10-25 j. what is the magnitude of b→?

Ametal ring 4.20 cm in diameter is placed between the north and south poles of large magnets with the plane of its area perpendicular to the magnetic field. these magnets produce an initial uniform field of 1.12 t between them but are gradually pulled apart, causing this field to remain uniform but decrease steadily at 0.240 t/s . (a) what is the magnitude of the electric field induced in the ring? (b) in which direction (clockwise or counterclockwise) does the current flow as viewed by someone on the south pole of the magnet?