If D is the diameter of impeller at inlet, w is the width of impeller at inlet and $V_f$ is the velocity of flow at inlet, then discharge through a centrifugal pump is equal to
- A. $\pi D V_f$
- B. $D V_f w$
- C. $\pi D V_f w$
- D. $\pi D w$
Answer: C. $\pi D V_f w$
Explanation: Discharge area is circumference times width ($\pi D w$). $Q = Area \times Velocity = \pi D w V_f$.