Application of the Force on a Current Carrying Conductor in a Magnetic Field - Loudspeaker

Loud Speaker

1. The loud speaker contains a cylindrical coil which is free to move in a radial magnetic field set up by a strong cylindrical permanent magnet.
2. The magnet has a central South Pole and a surrounding North Pole. The field lines are therefore radial and at right angles to the turns of the-coil.
3. When varying the current flows through the coil, a force of varying magnitudes will act on the coil. This will cause the coil to move to and fro according to the magnitude of the force.
4. The paper cone then vibrates to produce sound waves.