A speaker
Is producing sound, when
does a rarefaction occur?

Compression happens when molecules are forced, or pressed, together. Rarefaction is just the opposite, it occurs when molecules are given extra space and allowed to expand. ... In places like space, where there is no atmosphere, there is no sound. Let's look at the example of a stereo speaker.

before we can answer, we have to see the choices that are printed there with the question.   that's the only way we can point you to the correct one.

  the unit of the measure =

explanation:

  the property that is quantified by the energy needed per of material to raise the temperature by one.

  si unit of energy = joule (j)

  si unit of temperature = kelvin (k)

  si unit of mass of material = kilogram (kg)

the property that is quantified by the energy needed per of material to raise the temperature by one is called specific heat.

the unit of specific heat is