Correct Response: B. A centrifugal pump works according to the principle of an apparent centrifugal force acting on spinning objects when measured from a spinning reference frame. The spinning fluid experiences a force directed from the central inlet to the peripheral outlet. This apparent force comes from the spinning motion imparted by the impeller. In a turbine pump (A), the fluid flows in the direction of the axis of rotation of the vanes and not from the center to a peripheral exit. In a rotating vane pump (C), the fluid both enters and exits at the periphery of the circular chamber. The fluid is propelled in a semi-circular motion by a configuration of rotating vanes. In an external gear pump (D), the fluid is transported by the teeth of two interlocking gears in opposite directions around their outer circumference of the curved housing. This is yet another example where the fluid travels around a semicircular path from the outside of one end of the pump to the outside of the other end.
