Q1: An ideal fluid is

ANS:C - non-viscous & incompressible.

Certainly! Let's break down the characteristics of an ideal fluid being non-viscous and incompressible:

1. Non-viscous: Viscosity is a measure of a fluid's resistance to deformation or flow. A non-viscous fluid, also known as an inviscid fluid, lacks internal friction between its layers as it flows. This means that there is no dissipation of energy due to viscosity within the fluid. In practical terms, it implies that the fluid flows without any resistance to shearing forces, and there is no loss of mechanical energy due to internal friction. Examples of non-viscous fluids include ideal gases (under certain conditions) and some highly purified liquids.
2. Incompressible: An incompressible fluid is one in which the density remains constant regardless of changes in pressure. When a fluid is subjected to pressure, its volume may change in compressible fluids (like gases), but in incompressible fluids, such as liquids under normal conditions, the volume remains constant. This characteristic implies that the fluid's density does not change significantly with variations in pressure. In practical terms, it means that the fluid cannot be significantly compressed or made denser under typical conditions.

Together, the properties of non-viscous and incompressible fluids simplify fluid dynamics equations and analysis, making them easier to work with in theoretical and engineering contexts. Ideal fluid models, although theoretical, provide valuable insights into the behavior of real fluids under certain conditions and serve as a useful starting point for understanding fluid mechanics. However, it's important to note that no real fluid perfectly matches the properties of an ideal fluid, but in many practical applications, these assumptions can be reasonably accurate and useful for analysis and design purposes.