A diagram presenting the delivered head or pressure, total power consumption, and efficiency against volumetric flow rate for a centrifugal pump. The shape of the curve tends to show a fall or decrease in the delivered head or pressure with increasing volumetric flow rate while the power consumption increases with flow rate. The efficiency of the pump, which is expressed as the ratio of the work delivered by the fluid to the work input to the pump, rises with increasing delivered flow to a maximum known as the best efficiency point, and then decreases thereafter.