viscosity - Free MCQ Practice Test with solutions, UPSC Lucent

Viscosity is the measure of a fluid's resistance to flow. It represents the internal friction between layers of a fluid as they move past each other. Higher viscosity means the fluid flows more slowly, while lower viscosity indicates easier flow.

Factors affecting viscosity include temperature, density, and pressure. Higher temperatures decrease viscosity, whereas higher density and pressure increase viscosity.

Honey has a higher viscosity compared to water, making it flow more slowly due to its greater resistance to flow.

The SI unit of viscosity is the poise (Pa·s), named after the French physician Jean Louis Marie Poiseuille.

The viscosity of a liquid decreases with increasing temperature, as higher temperatures reduce intermolecular forces and increase the fluid's kinetic energy.

- Newton's Law of Viscosity is the correct answer.
- For gases, as temperature increases, viscosity generally increases because higher temperatures cause gas molecules to move faster and collide more frequently.
- This differs from liquids, where increasing temperature typically decreases viscosity.
- Newton's law provides a fundamental understanding of how fluid viscosity changes with temperature, particularly in gases.

Honey has the highest viscosity among the given options, as it is thicker and flows much more slowly compared to the other substances.

Viscosity is an important property in engineering, where it is crucial to understand and control the flow characteristics of fluids in various applications.

A rheometer is commonly used to measure the viscosity of a fluid. It applies shear stress to the fluid and measures the resulting deformation to determine its viscosity.

The viscosity of a fluid is mainly due to the friction between fluid particles as they move past each other, creating resistance to flow.

Newtonian fluids have a constant viscosity, regardless of pressure or temperature variations.

Mercury has the highest viscosity at room temperature among the given options. Its thick consistency contributes to its high resistance to flow.

High viscosity is associated with laminar flow, which is a smooth, ordered flow pattern without turbulence or eddies.

The concept of viscosity was first introduced by Sir Isaac Newton, who formulated the laws of motion and studied the behavior of fluids.

Viscosity is the parameter that determines the resistance to flow in a fluid. It depends on the internal friction and cohesive forces within the fluid.

Glycerin has the highest viscosity among the given options, making it thicker and more resistant to flow compared to air, water, or ethanol.

Newton's Law of Cooling states that the viscosity of most liquidsdecreases with increasing temperature. As the temperature rises, the intermolecular forces weaken, allowing the liquid molecules to move more freely and reducing the resistance to flow.

The viscosity of a gas increases with increasing temperature, as higher temperatures enhance the kinetic energy of gas molecules, causing them to move more rapidly, increasing molecular interactions and the mean free path between molecules.

Honey flows slowly compared to water due to its high viscosity. Viscous flow refers to the slow movement of a fluid, characterized by the fluid's resistance to flow and internal friction.

Newton's Law of Viscosity is mathematically represented by the equation F = μA(dv/dy), where F is the viscous force, μ is the dynamic viscosity, A is the area, and (dv/dy) is the velocity gradient along the direction of flow.