Heat Engines

1. A heat engine is a device that converts heat energy into mechanical work.
2. It operates between a hot reservoir and a cold reservoir.
3. The working principle is based on the First and Second Laws of Thermodynamics.
4. The efficiency of a heat engine is given by η = W/Q₁, where:
   • W is the work output.
   • Q₁ is the heat absorbed from the hot reservoir.

Entropy

1. Entropy is a measure of the disorder or randomness of a system.
2. The symbol for entropy is S, and its SI unit is joules per kelvin (J/K).
3. It quantifies the unavailability of a system's energy to perform useful work.
4. The Second Law of Thermodynamics states that entropy always increases in a spontaneous process.
5. ΔS = Q/T, where:
   • ΔS is the change in entropy.
   • Q is the heat exchanged.

Zeroth Law of Thermodynamics

1. The Zeroth Law of Thermodynamics defines the concept of thermal equilibrium.
2. If two systems are each in thermal equilibrium with a third system, they are in thermal equilibrium with each other.
3. This law provides the foundation for the definition of temperature.
4. Thermometers work based on the Zeroth Law.

First Law of Thermodynamics

1. The First Law of Thermodynamics is a statement of the conservat

1. Thermal conductivity is a material's ability to conduct heat.
2. It is denoted by the symbol k or λ.
3. The SI unit of thermal conductivity is watt per meter per kelvin (W/m·K).
4. 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.

1. Heat transfer is the movement of thermal energy from a region of higher temperature to a region of lower temperature.
2. There are three primary modes of heat transfer: conduction, convection, and radiation.

Conduction

1. Conduction is the transfer of heat through a material without the movement of the material itself.
2. It occurs mainly in solids, where particles are tightly packed.
3. The rate of conduction is described by Fourier’s Law: Q = -kA(dT/dx)

1. Heat capacity is the amount of heat energy required to raise the temperature of a body by 1 degree Celsius or Kelvin.
2. The SI unit of heat capacity is joule per kelvin (J/K).
3. 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.
4. 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.

1. Temperature is a measure of the average kinetic energy of the particles in a substance.
2. Heat is the transfer of thermal energy between systems due to a temperature difference.
3. There are three primary temperature scales used in thermodynamics: Celsius, Fahrenheit, and Kelvin.
4. The Celsius scale (°C) is widely used in most parts of the world and in scientific work.
5. In the Celsius scale, the freezing point of water is 0°C an

1. Surface tension is the property of a liquid's surface to resist external forces and minimize its surface area.
2. It is caused by the cohesive forces between liquid molecules, which are stronger at the surface.
3. The SI unit of surface tension is newton per meter (N/m).
4. Surface tension enables the formation of spherical droplets in liquids like water and mercury.
5. Capillary action is the ability of a liquid to flow in narrow spaces without external forces like gravity.
6. It occurs due to

1. Viscosity is a measure of a fluid's resistance to flow, caused by internal friction between fluid layers.
2. Fluids with higher viscosity flow more slowly, while those with lower viscosity flow more freely.
3. The SI unit of viscosity is the pascal-second (Pa·s), and the CGS unit is the poise.
4. Newtonian fluids obey Newton’s law of viscosity, where shear stress is directly proportional to the rate of shear strain.
5. Non-Newtonian fluids do not follow Newton’s law

1. 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.
2. 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.
3. Bernoulli’s equation