How is density defined in the provided material?

• A. Mass times volume.
• B. Mass divided by volume. The amount per unit size.
• C. Volume divided by mass.
• D. Mass.

Answer: (B)

Density is how much mass sits in a given amount of space. It’s defined as mass divided by volume, giving the amount of matter per unit volume. This is why the correct description is mass divided by volume. The product of mass and volume isn’t a density measure, and volume divided by mass gives the reciprocal of density (specific volume). Mass alone doesn’t tell you how much space the mass occupies, so it isn’t density. Common density units are kg/m^3 or g/cm^3.