Properties of an Ideal Fluid

An ideal fluid, also known as an inviscid fluid, is a theoretical concept used in fluid mechanics to simplify the analysis of fluid flow. It is important to understand the properties of an ideal fluid to better understand its behavior and how it differs from real fluids.

Incompressibility
An ideal fluid is considered to be incompressible. This means that its density remains constant regardless of the pressure applied to it. In other words, the volume of an ideal fluid does not change when subjected to external forces. Real fluids, on the other hand, can exhibit compressibility and can change their volume under pressure.

Compressibility
Option 'A' states that an ideal fluid is compressible, which is incorrect. In reality, an ideal fluid is not compressible. Compressibility refers to the ability of a fluid to be compressed or have its volume reduced under the application of external forces. In an ideal fluid, the spacing between molecules is considered to be constant, and any changes in pressure or force do not cause the fluid to compress or change its volume.

Shear Force
Option 'C' states that an ideal fluid has high shear force, which is incorrect. An ideal fluid is often assumed to have zero shear stress or shear force. Shear force refers to the force that acts parallel to a surface, causing one layer of the fluid to slide over an adjacent layer. In an ideal fluid, there is no internal friction or viscosity, which means there are no shear forces present.

Viscosity
Option 'D' states that an ideal fluid has a high value of viscosity, which is incorrect. Viscosity is a measure of a fluid's resistance to flow. An ideal fluid is assumed to have zero viscosity, meaning that it flows without any internal friction. Real fluids, such as water or oil, have non-zero viscosity and exhibit resistance to flow.

Therefore, the correct answer is option 'B': An ideal fluid is incompressible. It does not change its volume when subjected to external forces and is considered to have a constant density.