What is viscosity?
Answer
Viscosity is the internal friction of a fluid that opposes the relative motion between its adjacent layers, with SI unit pascal-second (Pa·s).
The working
Definition
Viscosity is the property of a fluid by which it resists the relative sliding of its layers. It acts like internal friction within the fluid.
Cause
When one layer of fluid moves faster than the next, a tangential dragging force develops between them that tries to slow the faster layer.
Coefficient
The coefficient of viscosity (η) links the viscous force to velocity gradient, with SI unit Pa·s (or poiseuille). Its CGS unit is the poise.
Behaviour
Liquids generally become less viscous as temperature rises, while gases become more viscous. Honey is more viscous than water.
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