Physics - Wyatt's Notes
Intuition
The most fundamental science: Physics describes the rules of the universe — from the smallest particles to the largest structures. It is the science of “why things work” at the deepest level, and it provides the foundation for all other sciences and engineering.
Why it matters: Physics underpins all technology — understanding mechanics lets you build bridges, understanding electromagnetism lets you build computers, and understanding quantum mechanics lets you build lasers and semiconductors.
The key insight: Physics progresses by finding unifications — the more phenomena a single theory explains, the deeper our understanding. This drive for unification is what makes physics the most elegant of the sciences.
Why This Matters
Physics is the most fundamental natural science — it seeks to explain the behaviour of matter and energy through mathematical laws. These notes provide rigorous, derivation-based coverage of undergraduate physics, building from classical mechanics through quantum theory. Understanding these concepts is essential for careers in physics, engineering, and related fields. Physics trains you to think precisely about the natural world, to model complex systems with mathematical equations, and to test theories against experimental evidence.
What You Will Find
- Classical Mechanics: Newton’s laws, Lagrangian and Hamiltonian mechanics, oscillations, and central forces. Classical mechanics describes all macroscopic motion through energy and momentum conservation. It is the foundation for engineering, astrophysics, and biomechanics.
- Electromagnetism: Electrostatics, magnetostatics, Maxwell’s equations, and electromagnetic radiation. Electromagnetism unifies electricity, magnetism, and light into a single force. It is the foundation for electronics, telecommunications, and optics.
- Quantum Mechanics: Wave functions, operators, angular momentum, perturbation theory, and entanglement. Quantum mechanics governs physics at atomic and subatomic scales. It explains the periodic table, chemical bonding, and semiconductor behaviour.
- Thermal Physics: Thermodynamics, statistical mechanics, and kinetic theory. Thermal physics connects microscopic particle behaviour to macroscopic observables like temperature and pressure. It explains phase transitions, heat engines, and the behaviour of gases.
- Optics: Wave optics, interference, diffraction, and polarisation. Optics describes how light propagates and interacts with matter. Applications include lasers, holography, optical fibres, and imaging systems.
Cross-References
- Introduction: Start here for an overview of the physics notes and navigation guidance.
- Classical Mechanics: Newtonian mechanics and conservation laws form the foundation of physics.
- Electromagnetism: Maxwell’s equations describe electric and magnetic fields and their interactions with matter.
- Quantum Mechanics: Wave functions and operators describe physics at atomic scales.
Common Mistakes
Confusing units across physical domains: Mixing CGS and SI units (e.g., Gauss vs Tesla for magnetic fields) gives wrong numerical answers. Always convert to a consistent unit system.
Forgetting that physics equations are only valid in certain regimes: Newtonian mechanics fails at relativistic speeds; classical electromagnetism fails at quantum scales. Check assumptions before applying formulas.
Neglecting dimensional analysis: Every valid physics equation must be dimensionally consistent. If units don’t balance, the equation is wrong or misapplied.
Overview
This section provides comprehensive study materials and resources. Content is organised to build understanding progressively, from foundational concepts to advanced applications.
Key Topics
- Core concepts and definitions
- Worked examples with step-by-step solutions
- Practice problems for self-assessment
- Cross-references to related topics
Study Tips
Begin with the introductory material before progressing to advanced topics. Use the practice problems to test your understanding and identify areas for further study.