Which unit would you expect to see for cytocentrifuge speed in a protocol?

• A. rpm
• B. kg
• C. mL
• D. L

Answer: (A)

Centrifuge speed is described by how fast the rotor spins, so it is expressed in revolutions per minute. This unit directly communicates the rotational velocity driving how cells are pelleted or deposited in cytocentrifugation. Mass (kg) and volumes (mL, L) are not speed measures, so they don’t describe how quickly the rotor turns. In some contexts you might see relative centrifugal force described in "g," but when the question asks for the unit of speed, revolutions per minute is the standard way to report it.