Viscosity is a measure of what property?

• A. Resistance to flow
• B. Temperature
• C. Mass
• D. Pressure

Answer: (A)

Viscosity measures how much a fluid resists flowing, due to internal friction between its layers as it moves. A liquid with high viscosity, like honey, flows slowly because the layers stick together more; a low-viscosity liquid, like water, flows easily because the internal friction is less. Temperature affects viscosity because heating often reduces the strength of intermolecular interactions, allowing flow to occur more readily, so viscosity typically decreases with higher temperature. Mass is just the amount of matter, not how easily it flows, and pressure is a force per area, which can influence flow rate in a system but does not define the fluid’s resistance to flow.