The acoustic variable density is measured in units of?

The acoustic variable density is measured in units of?

• A. kg/cm3
• B. kg/m3
• C. g/cm3
• D. lb/ft3

Answer: (A)

Density is mass per unit volume, and in ultrasound acoustics the standard unit is kilograms per cubic meter (kg/m^3). This SI unit keeps typical tissue densities (about 1000 kg/m^3) in a practical range. Using kilograms per cubic centimeter would express densities that are a million times larger than the same value in kg/m^3 (since 1 cm^3 = 1e-6 m^3), which is not how acoustic density is represented in this field. For reference, 1 g/cm^3 equals 1000 kg/m^3, and water is about 1000 kg/m^3. So the appropriate unit is kg/m^3.

Density is mass per unit volume, and in ultrasound acoustics the standard unit is kilograms per cubic meter (kg/m^3). This SI unit keeps typical tissue densities (about 1000 kg/m^3) in a practical range. Using kilograms per cubic centimeter would express densities that are a million times larger than the same value in kg/m^3 (since 1 cm^3 = 1e-6 m^3), which is not how acoustic density is represented in this field. For reference, 1 g/cm^3 equals 1000 kg/m^3, and water is about 1000 kg/m^3. So the appropriate unit is kg/m^3.