Physics studies matter, energy, motion, forces, fields, space and time through observation, experiment and mathematical models. Its scope ranges from subatomic particles to planets and galaxies. Quantum mechanics and relativity describe different physical regimes, while a complete theory that unifies quantum physics with gravity remains an open research goal.
This category groups introductory articles on quantum theory, electromagnetism, electrostatics and electron emission. Use the sections below to review definitions, physical models and engineering applications. Check each article’s assumptions and units before applying an equation to a practical problem.
