Which metric prefix denotes a factor of 10^-15?

The metric prefix that denotes a factor of 10^-15 is "Femto." In the metric system, prefixes are used to simplify the expression of units by providing a shorthand way to denote multiples or fractions of base units.

"Femto" specifically indicates one quadrillionth, or 1 divided by 1,000,000,000,000,000, which is equivalent to 10^-15. As a result, it is commonly used in fields such as physics and engineering, especially when dealing with very small quantities, such as measurements at the atomic or subatomic levels.

For clarity, the other prefixes mentioned refer to different values: "Pico" denotes a factor of 10^-12, which is one trillionth; "Atto," representing 10^-18, means one quintillionth; and "Yocto," which stands for 10^-24, represents a septillionth. Understanding these prefixes is foundational in scientific communication, especially when precision in measurements is paramount.