loudspeakers

Question 1

what do loudspeakers and headphones use the motor effect to do?

Answer 1

to convert variations in current in electrical circuits to the pressure variations in sound waves

Question 2

how do moving-coil loudspeakers
and headphones work?

Answer 2

1. a cone has a coil of wire wrapped around one end that is connected to an a/c electrical supply, a permanent magnet goes inside the coil of wire
2. as the current passes through the coil, it generates a magnetic field
3. the magnetic field from the coil interacts with the magnetic field from the permanent magnet, they either attract or repel
4. this produces a resultant force which causes the cone to move
5. when the current switches direction, the direction of the force on the cone reverses
6. causes the cone to move in and out, generating sound waves

Question 3

what does changing the frequency of the a/c supply change?

Answer 3

the frequency that the cone vibrates

Question 4

what will a higher frequency produce?

Answer 4

a higher pitched sound

Question 5

what happens if we increase the size of current?

Answer 5

we increase amplitude of the vibration, increasing volume of the sound