## The internal resistance of a liquid to flow is known as

A: Vapour pressure
B: Viscosity
C: Surface tension
D: Capillary action

## Internal Resistance of  Liquid

The magnitude of internal resistance or friction in a fluid which is measured by the force per unit area resisting the uniform flow is commonly known as Viscosity.

## What is Viscosity?

Other terms of viscosity are dynamic viscosity, absolute viscosity, or simple viscosity. In simple words, it is defined as internal resistance or friction present in a fluid.

## Symbol of Viscosity

It is represented by the Greek letter η (eta).

## Unit of Viscosity:

The SI unit of viscosity is the pascal second [Pa s]. The Gaussian unit of viscosity is the poise [P = dyne s/cm2]. While Ten poise equal one pascal second [10 P = 1 Pa s].

## Factors Affecting Viscosity

• Viscosity varies with the material. (Viscosity is a property of materials.)
• The viscosity of simple liquids…
• decreases with increasing temperature
• increases under very high pressures.
• The viscosity of gases…
• increases with increasing temperature
• is independent of pressure and density.