Correct Response

Correct Response

Both the dust particle and the candle flame will oscillate back and forth with the same frequency as the speaker membrane.

The physics:

Because the wavelength of the sound is large, the dust particle (or the flame) can be treated as a point particle which will move with its surroundings without being permanently displaced. Each will move back and forth due to the changes in pressure caused by the propagation of the sound wave through air.

Case Study Example: The motion of the dust particle

Previous slide Next slide Back to the first slide View Graphic Version