# Tags

A tag is a keyword or label that categorizes your question with other, similar questions. Using the right tags makes it easier for others to find and answer your question.

 Type to find tags:
 atomic-physics× 63 dark-energy× 63 topology× 63 fermions× 62 particles with an intrinsic angular momentum (i.e. spin) equal to a "half integer" number of fundamental units: $\frac{(2n+1)}{2} \hbar$ for integer $n$. Fermions are required to be in a … quantization× 62 ideal-gas× 62 maxwell-equations× 61 The four fundamental fundamental equations of electromagnetism. geometric-optics× 61 The subfield of optics in which light propagation is approximated in terms of rays. It mainly includes reflection and refraction on surfaces. dimensional-analysis× 61 gauss-law× 60 quarks× 60 variational-principle× 60 any of several principles that find the physical trajectory of a system by minimizing or maximizing some value computed over the proposed path (for instance geometric optics can be reproduced by insis… wavelength× 59 surface-tension× 59 Surface tension occurs due to the tendency of liquid molecules to favor their own kind. Surface tension is important in fluid multiphase systems typically at small length and velocity tensors× 59 mass-energy× 59 metric-tensor× 59 The variables used in general relativity to describe the shape of spacetime. If your question is about metric units, use the tag "units", and/or "si-units" if it is about the SI system specifically. hamiltonian× 59 drag× 59 dirac-equation× 57 aircraft× 57 causality× 57 inertial-frames× 57 information× 57 nuclear-engineering× 57 symmetry-breaking× 57 tensor-calculus× 56 resistors× 56 electrical-engineering× 55 observer× 54 interference× 54 hawking-radiation× 54 Radiation that comes from pair production quantum effects in close vicinity to an event horizon, leading to the potential for eventual evaporation of black holes. Two mirror particles are created wit… topological-field-theory× 54 renewable-energy× 53 Energy sources that do not rely on the consumption of an exhaustible fuel. Tidal, geothermal, and the direct and indirect solar energies (direct: photovoltaics, CSP, solar thermal; indirect: wind, wav… rotational-kinematics× 53 A tag for questions about rotational motion, including angular velocity and angular acceleration. physical-constants× 53