The discharge on a centrifugal pump ___ with the increase of head.

• A. Increases
• B. Fluctuates
• C. Remains the Same
• D. Decreases

Answer: (D)

For a centrifugal pump at a fixed speed, head and discharge are linked by the pump’s performance curve: as the head (the pressure the system demands) rises, the flow rate the pump can deliver falls. This happens because increasing head means more resistance for the fluid to overcome; the pump cannot push as much fluid through a higher-resistance path, so the discharge decreases. In fact, the curve shows the maximum head at near-zero flow, and head drops as flow increases. Therefore, when head goes up, the discharge goes down.