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Zeroth Law of Thermodynamics
- The Zeroth Law of Thermodynamics defines the concept of thermal equilibrium.
- If two systems are each in thermal equilibrium with a third system, they are in thermal equilibrium with each other.
- This law provides the foundation for the definition of temperature.
- Thermometers work based on the Zeroth Law.
First Law of Thermodynamics
- The First Law of Thermodynamics is a statement of the conservat
- Thermal conductivity is a material's ability to conduct heat.
- It is denoted by the symbol k or λ.
- The SI unit of thermal conductivity is watt per meter per kelvin (W/m·K).
- Fourier's Law describes heat conduction: Q = -kA(dT/dx), where:
- Q is the heat transfer rate.
- k is the thermal conductivity.
- A is the cross-sectional area.
- dT/dx is the temperature gradient.
- Heat transfer is the movement of thermal energy from a region of higher temperature to a region of lower temperature.
- There are three primary modes of heat transfer: conduction, convection, and radiation.
Conduction
- Conduction is the transfer of heat through a material without the movement of the material itself.
- It occurs mainly in solids, where particles are tightly packed.
- The rate of conduction is described by Fourier’s Law: Q = -kA(dT/dx)
- Heat capacity is the amount of heat energy required to raise the temperature of a body by 1 degree Celsius or Kelvin.
- The SI unit of heat capacity is joule per kelvin (J/K).
- Specific heat capacity is the amount of heat energy required to raise the temperature of 1 kilogram of a substance by 1 degree Celsius or Kelvin.
- The formula for specific heat capacity is c = Q / (m × ΔT), where:
- Q is the heat energy supplied.
- m is the mass of the substance.
- Temperature is a measure of the average kinetic energy of the particles in a substance.
- Heat is the transfer of thermal energy between systems due to a temperature difference.
- There are three primary temperature scales used in thermodynamics: Celsius, Fahrenheit, and Kelvin.
- The Celsius scale (°C) is widely used in most parts of the world and in scientific work.
- In the Celsius scale, the freezing point of water is 0°C an
- Surface tension is the property of a liquid's surface to resist external forces and minimize its surface area.
- It is caused by the cohesive forces between liquid molecules, which are stronger at the surface.
- The SI unit of surface tension is newton per meter (N/m).
- Surface tension enables the formation of spherical droplets in liquids like water and mercury.
- Capillary action is the ability of a liquid to flow in narrow spaces without external forces like gravity.
- It occurs due to
- Viscosity is a measure of a fluid's resistance to flow, caused by internal friction between fluid layers.
- Fluids with higher viscosity flow more slowly, while those with lower viscosity flow more freely.
- The SI unit of viscosity is the pascal-second (Pa·s), and the CGS unit is the poise.
- Newtonian fluids obey Newton’s law of viscosity, where shear stress is directly proportional to the rate of shear strain.
- Non-Newtonian fluids do not follow Newton’s law
- Bernoulli’s Theorem is a fundamental principle in fluid dynamics, stating that the total mechanical energy of an incompressible and non-viscous fluid remains constant along a streamline.
- The mathematical expression for Bernoulli’s equation is: P + ½ρv² + ρgh = constant, where:
- P is the pressure energy per unit volume.
- ½ρv² is the kinetic energy per unit volume.
- ρgh is the potential energy per unit volume.
- Bernoulli’s equation
- Pressure in a fluid is defined as the force exerted per unit area by the fluid on the walls of its container or any object in the fluid.
- The formula for pressure is: P = F/A, where P is pressure, F is force, and A is area.
- The SI unit of pressure is the Pascal (Pa), where 1 Pa = 1 N/m².
- In a static fluid, pressure increases with depth due to the weight of the overlying fluid, given by P = ρgh, w
- Fluids are substances that can flow and take the shape of their container, including liquids and gases.
- Density (ρ) is the mass per unit volume of a fluid, given by the formula ρ = m/V, where m is mass and V is volume.
- The SI unit of density is kg/m³.
- Pressure (P) is defined as the force exerted per unit area, expressed as P = F/A, where F is force and A is area.
- The SI