How does the viscosity of a fluid being pumped affect the operation of a spur gear pump?

Correct Answer: Option C — The viscosity of the fluid is relatively unimportant in the pump operation.

Spur gear pumps are designed to handle a wide range of fluid viscosities. While viscosity affects internal slippage and power requirements, the fundamental operating principle remains consistent. Unlike centrifugal pumps, which are highly sensitive to viscosity, gear pumps maintain relatively stable performance across varying fluid thicknesses within design limits.