Viscosity indicates the agility to flow at given _________.

• A. Temperatures
• B. Pressures
• C. Volumes
• D. Speeds

Answer: (A)

Viscosity describes a fluid’s resistance to flow, and it’s defined for a specific temperature. Temperature is the controlling factor because heating lowers viscosity, letting the fluid flow more easily, while cooling raises viscosity and slows the flow. In HVAC and lubrication contexts, oils are rated by how fluid they are at standard temperatures, since the same oil can behave very differently as temperature changes. So viscosity indicates the agility to flow at given temperatures.