Every physics term,
clearly explained.
842 curated entries across 14 fields — each with a definition, the governing formula, its SI unit and a worked example.
Effective Mass
A parameter that simplifies modeling electron and hole dynamics in a crystal lattice by treating them as free particles with a modified mass determined by energy band curvature.
Browse by field
Fourteen branches of physics, from classical mechanics to plasma.
Astrophysics, Cosmology & Relativity
Black Hole · Special Relativity · General Relativity and more
60 termsBiophysics & Medical Physics
Bioenergetics · Osmosis · Membrane Potential and more
70 termsClassical Mechanics
Impulse · Momentum · Force and more
60 termsCondensed Matter & Materials Physics
Semiconductor · Superconductivity · Crystal Structure and more
67 termsElectromagnetism & Electronics
Electric Charge · Voltage · Electric Current and more
63 termsFoundations of Physics
Energy · Scalar · Vector and more
60 termsGeophysics & Environmental Physics
Seismology · Richter Scale · Mantle Convection and more
60 termsMathematical & Computational Physics
Differential Equation · Fourier Transform · Laplace Transform and more
60 termsNuclear & Particle Physics
Half-Life · Radioactive Decay · Nuclear Fission and more
54 termsOptics
Reflection · Refraction · Diffraction and more
60 termsPlasma Physics
Debye Length · Plasma Frequency · Magnetohydrodynamics and more
60 termsQuantum & Atomic Physics
Wave-Particle Duality · Heisenberg Uncertainty Principle · Schrödinger Equation and more
55 termsThermodynamics & Statistical Physics
Entropy · Temperature · Zeroth Law of Thermodynamics and more
53 termsWaves, Oscillations & Acoustics
Frequency · Doppler Effect · Resonance and more
Formulas worth knowing
One cornerstone equation from each corner of the dictionary.
Black Hole
A region of spacetime where gravitational acceleration is so intense that nothing, including light, can escape beyond its event…
Biophysics & Medical PhysicsBioenergetics
The branch of biophysics and biochemistry studying energy transformation, transfer, and coupling mechanisms in living organisms.
Classical MechanicsImpulse
The vector quantity defined as the integral of a force over the time interval during which it acts, equal to the net change in…
Condensed Matter & Materials PhysicsSemiconductor
A class of crystalline solids possessing electrical conductivity between that of conductors and insulators, controllable by…
Electromagnetism & ElectronicsElectric Charge
A fundamental intrinsic physical property of subatomic particles that causes matter to experience an electrostatic force when…
Foundations of PhysicsEnergy
The quantitative property that must be transferred to a physical system to perform work on it, or to heat it.