Thermodynamics: Energy and Matter

• Physics is a natural science that studies matter, its motion, and behavior through space and time, and that studies the related entities of energy and force.
• Physics is one of the most fundamental scientific disciplines, and its main goal is to understand how the universe behaves.

Thermodynamics

• Thermodynamics studies energy, its transformations, and its relationship to matter.
• It addresses macroscopic system properties such as temperature, pressure, and volume, and their interrelations.
• The laws of thermodynamics govern energy and matter behavior in all physical processes.
• Energy is conserved, meaning it cannot be created or destroyed, only converted; this is the first law of thermodynamics.
• The second law of thermodynamics dictates that the entropy of an isolated system always increases or remains constant in a reversible process, where entropy measures disorder or randomness.
• The third law of thermodynamics states that as temperature approaches absolute zero, the entropy of a system approaches a minimum value.
• Key concepts include:
  • Energy is the capacity to do work.
  • Heat is the energy transfer between objects due to temperature differences.
  • Work is the energy transferred when a force causes object displacement.
  • Temperature measures the average kinetic energy of particles in a system.
  • Entropy measures the disorder or randomness of a system.
  • Enthalpy is a system's thermodynamic property, equaling its internal energy plus the product of its pressure and volume.
• Thermodynamics finds applications in:
  • Power generation
  • Refrigeration
  • Chemical reactions
  • Material science

Electromagnetism

• Electromagnetism studies the electromagnetic force, a fundamental force of nature.
• It governs interactions between electrically charged particles, encompassing electric and magnetic phenomena.
• Key concepts include:
  • Electric charge, a fundamental property causing matter to experience force in an electric field.
  • Electric field, a force field surrounding an electric charge.
  • Magnetic field, a force field surrounding a moving electric charge or magnetic dipole.
  • Electric current, the flow of electric charge.
  • Voltage, the electric potential difference between two points.
  • Resistance, measuring the difficulty of electric current flow through a material.
  • Capacitance, measuring a capacitor's ability to store electric charge.
  • Inductance, measuring an inductor's ability to store energy in a magnetic field.
• Maxwell's equations, a set of four equations, describe the behavior of electric and magnetic fields.
• Applications of electromagnetism include:
  • Electronics
  • Communications
  • Power generation
  • Medical imaging

Classical Mechanics

• Classical mechanics studies the motion of macroscopic objects.
• It's based on Newton's laws of motion, relating force, mass, and acceleration.
  • An object remains at rest or in motion at a constant velocity unless acted upon by a force - Newton's First Law of Motion
  • The acceleration of an object is directly proportional to the net force and inversely proportional to its mass (F = ma) - Newtons Second Law of Motion
  • For every action, there is an equal and opposite reaction - Newtons Third Law of Motion
• Key concepts:
  • Displacement: The change in position of an object.
  • Velocity: The rate of change of displacement with respect to time.
  • Acceleration: The rate of change of velocity with respect to time.
  • Force: An interaction that can change an object's motion.
  • Mass: An object's resistance to acceleration.
  • Momentum: The product of an object's mass and velocity.
  • Energy: The capacity to do work.
• Applications:
  • Engineering
  • Astronomy
  • Sports

Quantum Physics

• Quantum physics studies matter and energy behavior at atomic and subatomic levels.
• It's based on the quantization of energy, momentum, angular momentum, and other quantities, meaning they exist in discrete values.
• Key concepts include:
  • Wave-particle duality: All matter exhibits both wave-like and particle-like properties.
  • Superposition: A quantum system exists in multiple states simultaneously.
  • Entanglement: Two or more quantum systems become linked, sharing the same fate regardless of distance.
  • Uncertainty principle: There's a fundamental limit to the precision with which certain pairs of physical properties, like position and momentum, can be known simultaneously.
  • Quantum tunneling: A particle passes through a potential barrier even without sufficient energy to overcome it classically.
• Applications:
  • Lasers
  • Transistors
  • Medical imaging
  • Quantum computing

Relativity

• Relativity, developed by Albert Einstein, is a theory of space, time, and gravitation comprising special and general relativity.
• Special relativity addresses space and time relationships for objects moving at constant velocity.
  • The speed of light is constant for all observers.
  • Time dilation occurs, where time passes slower for moving objects relative to stationary observers.
  • Length contraction occurs, where the length of a moving object appears shorter to a stationary observer.
  • Energy and mass are interchangeable (E = mc^2), demonstrated by mass-energy equivalence.
• General relativity addresses gravity's effects on space and time.
  • Gravity is the curvature of space-time caused by mass and energy.
  • Gravitational lensing, the bending of light around massive objects, occurs.
  • Black holes are regions with gravity so strong nothing can escape.
  • Gravitational waves are ripples in space-time caused by accelerating massive objects.
• Applications include:
  • GPS
  • Particle physics
  • Cosmology