In this Physics video in Hindi we explained viscosity and viscous force for class 11. We derived the formula for viscous force and explained the cofficient of viscosity. The viscous force is proportional to the area of contact and the speed of the top layer. This orce is inversely proportional to the distance between top and bottom layer. The constant of proportionality is known as the coefficient of viscosity. The SI unit for coefficient of viscosity is pascal second. Another unit is poise. 10 poise = 1 pascal second.
Most of the fluids are not ideal ones and offer some resistance to motion. This resistance to fluid motion is like an internal friction analogous to friction when a solid moves on a surface. It is called viscosity. This force exists when there is relative motion between layers of the liquid. Suppose we consider a fluid like oil enclosed between two glass plates. The bottom plate is fixed while the top plate is moved with a constant velocity v relative to the fixed plate. If oil is replaced by honey, a greater force is required to move the plate with the same velocity. Hence we say that honey is more viscous than oil. The fluid in contact with a surface has the same velocity as that of the surfaces. Hence, the layer of the liquid in contact with top surface moves with a velocity v and the layer of the liquid in contact with the fixed surface is stationary. The velocities of layers increase uniformly from bottom (zero velocity) to the top layer (velocity v). For any layer of liquid, its upper layer pulls it forward while lower layer pulls it backward. This results in force between the layers. This type of flow is known as laminar. The layers of liquid slide over one another as the pages of a book do when it is placed flat on a table and a horizontal force is applied to the top cover.
Previous videos -
🔴 Introduction to 'Mechanical Properties of Fluids' for Class 11
• 🔴 Mechanical Propertie...
🔴 Fluid Pressure
• 🔴 FLUID - 2 || Fluid P...
🔴 Pascal's Law (Part 1)
• 🔴 Pascal's Law (Part 1...
🔴 Pascal's Law (Part 2)
• 🔴 Pascal's Law (Part 2...
🔴 Hydrostatic Paradox
• 🔴 Hydrostatic Paradox ...
🔴 Mercury Barometer
• 🔴 Mercury Barometer ||...
🔴 U-Tube Manometer
• 🔴 U-Tube Manometer || ...
🔴 Archimedes' Principle
• ARCHIMEDES' PRINCIPLE ...
🔴 Streamline flow and Turbulent flow
• 🔴 Streamline Flow and ...
🔴 Equation of Continuity
• 🔴 Equation of Continui...
🔴 Bernoulli's Theorem
• 🔴 Bernoulli's Theorem ...
🔴 Torricelli's Law
• 🔴 Torricelli's Law || ...
🔴 Venturi Meter || Measuring the Speed of Fluid
• 🔴 VENTURI METER || Mea...
🔴 MAGNUS EFFECT and DYNAMIC LIFT
• 🔴 MAGNUS EFFECT and DY...
🔴 Click here to watch the whole playlist on 'Mechanical Properties of Fluids' for Class 11 :
• 🔴 Mechanical Propertie...
Негізгі бет 🔴 VISCOSITY || for Class 11 in HINDI
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