During agitation of liquids, the

• Froude number is independent for the curves between power number and Reynolds number in baffled system.
• Power number becomes independent of impellers Reynolds number at high Reynolds number, but is dependent on the geometry of the impeller.
• Froude number is used to account for the effect of surface (e.g., the centre vortex) on the power number.
• all (a), (b) and (c).