Question

Define Viscosity.

Answer 1

Hint: Viscosity is known as the resistance of a fluid to flow. To put it plainly, we may conclude that honey is thicker than water; honey, in turn, is more viscous than water. Viscosity depends upon the density of the fluid.

Complete step by step answer
Viscosity is known as the measure of a fluid's resistance to gradual shear deformation or tensile stress. The viscosity of the fluid is, at a certain rate, a measure of its deformation resistance.
In terms of the proportion of shearing stress to the velocity gradient in a fluid, viscosity is measured. If a sphere is dropped into a fluid, using the following formula, the viscosity can be determined:
 $\eta ={\displaystyle \frac{2ga2(\mathrm{\Delta }\rho )}{9v}}$
Where to,
The difference in density between the fluid and the sphere examined is $\mathrm{\Delta }\rho$
 $a$ is the radius of the field.
The acceleration due to gravity is $g$ .
 $v$ is the speed of the sphere.
Where to,
 $v$ = distance traveled by sphere/ time taken to travel the distance
In Pascal seconds, viscosity is calculated in (Pa s). The more viscous a fluid is, the more resistance it gives to any object within it moving. While all liquids have a certain viscosity value, liquid viscosity is usually known to be high or low, and water viscosity is maintained as a benchmark.
For e.g., water viscosity is $0.001$ Pa s, air viscosity is $0.000019$ Pa s, and motor oil viscosity is 1. The viscosity of liquids often decreases as the temperature rises, although with the rise in temperature, it increases for gases.

Note
Viscosity, as studied, is the measure of fluid friction. There are two ways to calculate the viscosity of a fluid:
-Dynamic Viscosity (Absolute Viscosity)
-Kinematic Viscosity
Between the two viscosity tests, one can get confused and assume them to be one and the same. They have major variations in fact between them. Kinematic viscosity is more useful than absolute or dynamic viscosity for a couple of applications.