What unit corresponds to Mg/cm², often used in XRF readings?

The unit Mg/cm² stands for milligrams per square centimeter. This is significant in the context of X-ray fluorescence (XRF) readings, as these readings measure the concentration of lead or other heavy metals on a surface. XRF analysis produces results in terms of mass per unit area, which is why the unit milligrams per square centimeter is appropriate. It allows for a clear understanding of how much lead is present on a material's surface, aiding in assessments for lead hazards in various environments.

In contrast, the other units provided refer to different measurements. Micrograms per centimeter squared is a smaller measurement that is sometimes used but does not correspond to the milligram scale relevant in much of the lead assessment context. Milliliters per cubic centimeter would refer to a volume measurement rather than a mass per area, making it unsuitable here. Likewise, micrograms per cubic centimeter is a unit that relates to density rather than surface concentration, which is not applicable for XRF readings that focus specifically on the mass of a substance per area. Thus, identifying milligrams per square centimeter as the correct answer directly correlates with the intended application of XRF in lead assessment tasks.