A femtogram (fg) is a metric unit of mass in the International System of Units (SI). It represents one quadrillionth of a gram or 10^-15 grams. The metric system is a decimal-based system of measurement used worldwide, and it is particularly useful for expressing extremely small quantities of mass.
To provide context for the size of a femtogram:
Femtograms are primarily used in advanced scientific and technical fields, particularly in situations where measuring the tiniest quantities of substances or particles is critical. Some common applications of femtograms include: