Physics

Articles about matter, energy, forces and physical laws.

Articles in this category: 687 Updated: April 29, 2026 Page 5 / 15

Fermion

Fermion: elementary particles that make up matter

Fermionic condensate

Ferromagnetism

Ferromagnetism

Feynman diagram

Feynman diagram: visual language for particle interactions

Field (physics)

Field strength

Filament

Filament: elongated structures across physics, astronomy, and biology

Fire triangle

First law of thermodynamics

First law of thermodynamics

First law of thermodynamics (conservation of energy)

The first law of thermodynamics states that energy cannot be created or destroyed, only transformed. It quantifies exchanges of heat and work and applies to closed systems, underpi

Fluid

Fluid dynamics

Fluid dynamics: principles, history, and applications

Fluid mechanics

Fluid statics

Fluorescence

Fluorescence: light emission by energized materials

Flux

Flux: concept, definitions, examples, and uses in science and mathematics

Flywheel

Flywheel

Focal length

Focus (optics)

Focus (optics)

Focus (optics): image points, limits, and practical implications

In optics, a focus is where light from a point source is brought together to form an image. This article explains how focus is produced, real vs virtual images, practical limits an

Foot-pound force

Foot‑pound force (ft·lbf)

Force

Force

Force (physics): definition, types, and effects

A concise encyclopedia article on force: its definition in physics, vector nature, contact vs. field forces, Newton’s laws, the four fundamental forces, history, examples, and prac

Force field

Force field — physical fields and fictional energy barriers

Foucault pendulum

Frame of reference

Frame-dragging

Frame dragging (Lense–Thirring effect)

Free fall

Free fall

Free fall (physics)

Free fall: motion under gravity alone. Overview of definition, equations, history, examples (projectiles, skydivers, spacecraft), terminal velocity and distinctions like weightless

Free-electron laser

Free-electron laser (FEL): principles, history and applications

Frequency

Fresnel lens

Fresnel lens — design, history and applications

Friction

Fundamental force

Fundamental force (four fundamental interactions)

Fusion power

Fusion power: principles, development, and prospects

G-Force

G-force: acceleration relative to gravity and its effects

Gamma ray

Gas-filled tube

Gas-filled tube: principles, history, types, and applications

Gauge boson

Gauss (unit)

Gauss (unit of magnetic flux density)

Gauss's law

Gauss's law: statement, meaning, history and applications

Gauss's law for magnetism

Geiger–Marsden experiment

Geiger–Marsden experiment (Gold foil or Rutherford experiment)

General relativity

General relativity: Einstein’s theory of gravitation and spacetime

Giant magnetoresistance

Giant magnetoresistance (GMR): principles, history and applications

Gluon

Gluon (carrier of the strong interaction)

Grand unification theory

Gravitational constant

Gravitational constant

Gravitational constant (G): definition, measurement and significance

The gravitational constant G quantifies the strength of Newtonian gravity. This article explains its meaning, units, measurement history, roles in physics, and common confusions su

Gravitational energy

Gravitational energy — concepts, formulas, and practical examples

Gravitational field

Gravitational singularity

Gravitational wave

Gravitational Waves: Theory, Astrophysical Sources, and Detection