physics

[deleted-67444]

sir
I am a teacher (physics).My Question is given below.
In which direction the flux lines of magnets moves in loudspeaker magnets?please explain?
thankx,
narendran

[deleted-71588]

I'm confused. There are two sets of magnetic fields in a simple axial loud speaker. One is an axial voice coil (electro magnet) attached to a cone that is used to move air. The magnetic field from this coil is toroidal as if there was a simple N-S or S-N magnet on the axis of some varying instantaneous strength (depends on the instantaneous current direction and strength). There is a permanant magent (usually cylindrical) typically with a "U style keeper" that is used to concentrate a permanent axial magnetic field around the voice coil such that the two fields will either attract (cone moves toward the permanant magnet) or repel (cone moves away from the permanent magnet).