The fundamental assumptions of Bernoulli's equation are: (1) Ideal fluid with negligible/low viscosity (inviscid flow), (2) Incompressible fluid (constant density $\rho$), (3) Steady, streamline/laminar flow along a streamline, and (4) Irrotational flow without energy addition or dissipation.

A Multistage Centrifugal pump uses several impellers mounted on a single shaft in series. Each stage adds kinetic energy and pressure head smoothly and steadily without pulsating discharge, completely avoiding the violent shock waves (water hammer effect) typical of reciprocating plunger pumps.

Statement (1) is false: Specific speed ($N_s = \frac{N\sqrt{Q}}{H^{3/4}}$) is defined as the rotational speed of a geometrically similar model pump which delivers unit discharge ($1\text{ m}^3/\text{s}$) under unit head ($1\text{ m}$). It is NOT simply the operational rpm at which a pump works best. Statement (2) is true: Specific speed is a fundamental shape parameter and characteristic number widely used by engineers to classify impeller geometry and compare performance across pump designs.