Sound is generated by the speaker cone vibrating in different ways. The cone vibrates as different magnetic forces act on the current-carrying coil. Why do the magnetic forces acting on the coil change as the current running through the coil changes?
A.
because the current causes the magnet to lose power
B.
because coils of wire are not usually attracted to magnets
C.
because the current causes the magnet to gain power
D.
because the current generates a magnetic field around the coil