Question

You place this device in a loudspeaker and provide an EMF through the coil. Draw the rest of the loudspeaker and briefly explain how outgoing sound waves are generated.

a) Electromagnetic waves create sound vibrations
b) Vibrations in the coil produce electromagnetic waves
c) Sound waves are generated by static electricity
d) Outgoing sound waves have no relation to the EMF

Answer 1

A loudspeaker generates sound by using an EMF to create a varying current in a coil, which in turns vibrates the attached speaker cone to produce sound waves in the air.

Step-by-step explanation:

To understand how a loudspeaker works, we need to consider the role of electromagnetic fields in sound production. When an electromotive force (EMF) is applied to the loudspeaker's coil, it creates a varying current. According to physics, a varying current will produce oscillating electric and magnetic fields that propagate away from the coil. In the case of a loudspeaker, the coil is attached to a cone, which moves back and forth in response to the changing electromagnetic force exerted by the coil within the magnetic field of a permanent magnet. This movement of the cone pushes on the air around it, creating pressure waves in the air—these are the sound waves we hear.

Therefore, in the context of the loudspeaker, option b) 'Vibrations in the coil produce electromagnetic waves' is partially correct, but the complete answer is that the vibrations in the coil cause the speaker cone to move, which then produces sound waves. Electromagnetic waves themselves are not sound but can lead to sound production when they cause a medium, like a speaker cone, to vibrate.