Mechanical Properties Of Fluids Class 11 Notes

Fluids are the substances which move or flow in a certain direction when an external force is applied to them. Fluids can be either gases or liquids. However, when we study fluids and their mechanical properties, we come across two topics namely hydrodynamics and hydrostatics.

What is Hydrostatic?

Hydrostatic is basically concerned with fluids at rest while hydrodynamics deals with fluids which are in motion.

What is Pascal’s Law?

When a fluid is at rest, the pressure on the liquid is the same at all points provided, they are of the same height. The change in pressure which has been applied on the fluid which is enclosed can be transmitted undiminished to every point of the fluid and the container vessel’s walls.

When an incompressible fluid is passing between every second in a pipe of non-uniform cross-section, the volume will be the same as the steady flow. Bernoulli’s principle is an equation which states the conservation of energy of non-viscous fluid motion in a steady state.

What is Reynold’s Number?

Reynolds number is referred to the onset of turbulence in a fluid flow which can be determined by a dimensionless parameter.

What is Surface Tension?

It is referred to the force per unit length which is acting on the plane of the interface between the bonding surface and the liquid. It is the amount of the extra energy which the molecules at the interface have when compared to the interior.

Important Questions

  1. Explain why
  • (a) The blood pressure in humans is greater at the feet than at the brain
  • (b) Atmospheric pressure at a height of about 6 km decreases to nearly half of its value at the sea level, though the height of the atmosphere is more than 100 km
  • (c) Hydrostatic pressure is a scalar quantity even though the pressure is force divided by area.
  1. Explain why
  • (a) The angle of contact of mercury with glass is obtuse, while that of water with glass is acute.
  • (b) Water on a clean glass surface tends to spread out while mercury on the same surface tends to form drops. (Put differently, water wets glass while mercury does not.)
  • (c) The surface tension of a liquid is independent of the area of the surface
  • (d) Water with detergent dissolved in it should have small angles of contact.
  • (e) A drop of liquid under no external forces is always spherical in shape Students can check out some of the important chapter topics below;
    • Pressure
    • Viscosity
    • Streamline Flow
    • Surface Energy
    • Surface Tension
    • Atmospheric Pressure and Gauge Pressure
    • Pressure in Bubbles, Drop and Capillary Rise
    • Bernoulli’s Principle
    • Reynold’s Number
    • Hydraulic Machines
    • Pascal’s Law

In addition to this, students can also download the sample papers, important questions and last year question papers of physics class 11 below. Physics Sample Paper Class 11

Physics Important Questions Class 11

Previous Year Question Paper Of Physics Class 11 CBSE

Stay tuned to Byju’s and learn physics topics with engaging video lectures and class wise notes.

Also Read:


Practise This Question

Select the correct diagram for the π 2py - orbital: