Charges of +3 µC and –5 µC are 2 mm from each other. The –5 µC charge is replaced with a +5 µC charge. How will the electrical force between the charges compare with the original force?

a. same force, but in the opposite direction
b. same force, but in the same direction
c. greater force, but in the opposite direction
d. greater force, but in the same direction

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?