In which units can amplitude exist?

Amplitude refers to the maximum extent of a vibration or oscillation, measured from the position of equilibrium. In the context of ultrasound and physical waves, amplitude can represent different quantities depending on the specific wave being discussed.

For ultrasound waves, amplitude can be related to pressure variations. This means that amplitude can indeed be expressed in Pascals, which is a unit of pressure. In the context of ultrasound, higher amplitude corresponds to greater pressure differences within the wave, which can be significant in assessing tissue characteristics during imaging.

Additionally, amplitude is also relevant to density when considering how sound waves travel through different mediums. Since density can affect how sound travels and interacts with tissues, measuring amplitude in terms of density provides useful information about the medium's properties.

Thus, the answer indicating that amplitude can exist in Pascals (a measure of pressure) and density (in g/cm³) correctly encompasses the various units relevant in the context of ultrasound and physics.