Surface Tension and Molecular Theory class 11 physics chapter 9 Mechanical Properties of fluids Notes with definition, formula, units, dimensional formula, sphere of influence, FAQs, MCQs, true/false, fill in the blanks, very short, short & long question answers based on NCERT - Physicskund  Surface Tension Definition: Surface tension is the property of a liquid at rest by virtue of which its free surface tends to occupy the minimum possible surface area and behaves like a stretched elastic membrane . Mathematical Definition Surface tension is defined as the force acting per unit length on either side of an imaginary line drawn tangentially on the free surface of a liquid. The force acts normal (perpendicular) to the imaginary line. $$ T=\frac{F}{l} $$ Where, T = Surface tension F = Force acting on either side of the imaginary line l = Length of the imaginary line Units of Surface Tension System Unit SI N m -1 CGS dyne cm -1 Dimensiona...

Drops and Bubbles Small liquid drops and soap bubbles are generally spherical because of surface tension . A sphere has the minimum surface area for a given volume, so it possesses the minimum surface energy. Surface tension always tries to reduce the surface area of a liquid, causing the drop to become spherical. A liquid drop has only one liquid-air surface , whereas a soap bubble has two liquid-air surfaces (inner and outer). Due to surface tension, the pressure inside the drop or bubble is always greater than the pressure outside. This pressure difference is called Excess Pressure . Principle of Derivation The derivation of excess pressure is based on the principle of conservation of energy. When a liquid drop expands slightly: The excess pressure inside the drop performs work to increase its size. The surface area of the drop increases. As the surface area increases, the surface energy also increases. Therefore, Work Done by Excess Pressure=Increase in...

 Notes : Define Viscosity , Coefficient , Newton law, Units , Dimensions  class 11 physics chapter 9 Mechanical Properties of fluids - Physics Kund  Introduction Fluids (liquids and gases) can flow because their molecules are free to move. During flow, one layer of a fluid moves relative to another layer. Due to intermolecular forces, a resistive force develops between adjacent layers. This property of a fluid is called viscosity . It is one of the most important mechanical properties of fluids and explains why some liquids like water flow easily while others such as honey, glycerine, and engine oil flow slowly. An ideal fluid is a hypothetical fluid that is incompressible and has zero viscosity. In reality, every fluid possesses some viscosity. Viscosity Viscosity is the property of a fluid by virtue of which it opposes the relative motion between its adjacent layers. It is also known as the internal friction of a fluid. Whenever different layers of a fluid m...

Learn Dynamic Lift Class 11 Physics chapter 9 Mechanical Properties of fluids with easy notes, Bernoulli's Principle, Magnus Effect, Aerofoil, MCQs, FAQs, True/False, and important questions - Physics Kund  Dynamic Lift Dynamic lift is the force that acts on a body, such as an airplane wing, a hydrofoil or a spinning ball, by virtue of its motion through a fluid. Dynamic lift is explained by Bernoulli's principle . When a body moves through a fluid, the fluid velocity may become different on its two sides. According to Bernoulli's principle, the region where the fluid velocity is higher has lower pressure, while the region where the velocity is lower has higher pressure. This pressure difference produces an upward force called dynamic lift . Ball Moving Without Spin Figure shows the streamlines around a non-spinning ball moving relative to a fluid. The streamlines are symmetrical above and below the ball. Therefore, the velocity of air above and below the ball at c...

Learn Streamline Flow (Steady Flow) Class 11 Physics Chapter 9 mechanical properties of Fluids with complete notes, definition, characteristics, formulas, continuity equation, MCQs, FAQs, and solved questions. Streamline Flow (Steady Flow) Streamline flow , also known as Steady Flow or Laminar Flow , is one of the most important types of fluid flow. In this type of flow, every fluid particle follows a fixed path called a streamline . The velocity of the fluid at any fixed point remains constant with time, making the flow smooth and orderly. Definition Streamline (Steady) Flow: The flow of a fluid in which the velocity of every fluid particle at a given point remains constant with time is called streamline flow or steady flow . In streamline flow, each fluid particle follows the same fixed path without disturbing the neighboring particles. Explanation Consider a fluid flowing through a pipe along the path ABC . Let the velocity at point A be v 1 . Let the velocit...

Equation of Continuity | Fluid Mechanics | Class 11 Physics | NCERT Explained in Simple English  Equation of Continuity The Equation of Continuity is one of the most important equations in fluid dynamics. It is based on the Law of Conservation of Mass , which states that mass can neither be created nor destroyed. Therefore, during the steady flow of a fluid through a pipe, the mass entering one end of the pipe per second is equal to the mass leaving the other end per second, provided there is no source or sink of fluid between the two sections. Law Expressed by the Equation of Continuity The equation of continuity expresses the Law of Conservation of Mass . Statement of the Equation of Continuity For the steady flow of a fluid through a tube of varying cross-sectional area, the mass flow rate remains constant at every cross-section of the tube. Assumptions The fluid flow is steady (streamline flow). There is no leakage or addition of fluid between two sections. ...

 Notes : Chapter 9 Mechanical Properties of Fluids Class 11 Physics - Physicskund   Pressure   Density Pascal's Law Pressure Exerted by a Liquid Column (Hydrostatic Pressure) Variation of pressure with Depth - Gauss Pressure  Hydrostatic Paradox Atmospheric pressure  Mercury Barometer Open tube Manometer Hydraulic machines Streamline Flow Laminar and Turbulent Flow   Equation of Continuity Bernoulli Principle Speed of Efflux : Torricelli's Law Dynamic Lift Viscosity   Stokes's Law Surface Tension Surface Energy   Angle of Contact Drops and Bubbles   Capillary Rise