Home Wikituition Browse all terms Categories
Random term

Browse the dictionary

842 terms · page 29 of 36


A–Z
All A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Plasma Physics

Reversed Field Pinch (RFP)

A toroidal magnetic confinement device in which the toroidal magnetic field self-reverses direction near the outer edge of the plasma…

B_toroidal reverses direction near plasma edge (q < 1) T (Toroidal Field B_T)
Thermodynamics & Statistical Physics

Reversible Process

An idealized thermodynamic process that can be reversed by infinitesimal changes in system variables without leaving any net trace on…

dS_universe = 0 N/A
Classical Mechanics

Reynolds Number

A dimensionless quantity in fluid mechanics predicting flow patterns, equal to ratio of inertial forces to viscous forces.

Re = (ρ v L) / η Dimensionless
Geophysics & Environmental Physics

Richter Scale

A base-10 logarithmic scale quantifying earthquake magnitude based on the maximum amplitude of seismic waves recorded on a seismograph.

M_L = log₁₀(A / A₀), M_w = ⅔ log₁₀(M₀) - 6.07 Logarithmic Magnitude (M_L / M_w)
Electromagnetism & Electronics

RL Circuit

An electrical circuit containing resistors and inductors, characterized by an exponential delay in current growth and decay governed by…

I(t) = (V₀ / R) (1 - e^(-t / τ)), τ = L / R s (Seconds)
Electromagnetism & Electronics

RLC Circuit & Resonance

An electrical circuit containing a resistor, inductor, and capacitor whose total impedance reaches a minimum at the resonant frequency.

f_res = 1 / (2π √(L C)), Z = √(R² + (X_L - X_C)²) Hz (Frequency), Ω (Impedance)
Electromagnetism & Electronics

RMS Current

The Root-Mean-Square value of an alternating current (AC), representing the equivalent direct current (DC) that delivers equal average…

I_rms = I_peak / √2 ≈ 0.707 I_peak A (Amperes)
Classical Mechanics

Rotational Kinetic Energy

The kinetic energy possessed by a body due to its rotation about an axis.

KE_rot = ½ I ω² J
Mathematical & Computational Physics

Round-off Error

The difference between the exact mathematical value of a function and the value computed using finite-precision floating-point arithmetic.

Machine Epsilon ε_mach ≈ 2⁻⁵³ ≈ 1.11 × 10⁻¹⁶ (IEEE 754 Double Precision) Floating-Point Precision Error
Mathematical & Computational Physics

Runge-Kutta Methods

A family of iterative numerical integration algorithms used to solve ordinary differential equations with high accuracy.

RK4: y_(n+1) = y_n + (h / 6) (k₁ + 2 k₂ + 2 k₃ + k₄) Numerical ODE Integration Method
Quantum & Atomic Physics

Rydberg Constant

A fundamental physical constant expressing the limiting wavenumber of atomic spectral lines for infinitely heavy nuclei.

R_∞ = (m_e e⁴) / (8 ε₀² h³ c) ≈ 1.097373 × 10⁷ m⁻¹ m⁻¹ (Reciprocal Meters)
Plasma Physics

Saha Ionization Equation

A thermodynamic relation expressing the ionization state of a plasma in thermal equilibrium as a function of temperature and electron…

(n_i+1 n_e) / n_i = (2 g_i+1 / g_i) (2 π m_e k_B T / h²)^(3/2) e^(-E_ion / (k_B T)) m⁻³ (Ionization Balance Density)
Foundations of Physics

Scalar

A physical quantity that is completely specified by its magnitude (value and unit) alone, possessing no direction.

Various
Foundations of Physics

Scalar Product

An algebraic vector operation that multiplies two vectors to yield a scalar equal to the product of their magnitudes and the cosine of the…

A · B = |A||B| cos θ = Ax Bx + Ay By + Az Bz Various
Quantum & Atomic Physics

Schrödinger Equation

A fundamental partial differential equation describing how the quantum wave function of a physical system evolves deterministically over…

i ℏ (∂ψ / ∂t) = Ĥ ψ, Ĥ ψ = E ψ Energy (Eigenvalue E in Joules or eV)
Astrophysics, Cosmology & Relativity

Schwarzschild Radius

The physical radius defining the event horizon of a non-rotating, spherically symmetric black hole of mass M.

R_s = 2 G M / c² ≈ 2.95 km × (M / M_☉) Meters or Kilometers
Foundations of Physics

Scientific Law

A concise verbal or mathematical statement that describes a universal, consistently observed relationship in nature under specified…

N/A
Foundations of Physics

Scientific Method

An empirical, iterative process for investigating natural phenomena through observation, hypothesis formulation, experimentation, and…

N/A
Foundations of Physics

Scientific Notation

A standardized method of expressing very large or very small numbers in the format a × 10ⁿ, where 1 ≤ |a| < 10 and n is an integer.

a × 10^n Dimensionless
Foundations of Physics

Scientific Theory

A comprehensive, well-substantiated explanation of a broad aspect of nature supported by extensive empirical evidence and repeated testing.

N/A
Nuclear & Particle Physics

Scintillation Counter

A radiation detection instrument that measures ionizing radiation by detecting flashes of light (scintillations) produced in a luminescent…

Ionizing Radiation → Scintillation Photons → Photoelectrons Pulse Counts / Energy Spectra
Geophysics & Environmental Physics

Sea Level Rise

The ongoing increase in global mean sea level caused by thermal expansion of warming ocean water and meltwater input from glaciers and ice…

Δh_sea = Δh_thermosteric + Δh_eustatic (Thermal Expansion + Meltwater) mm/year (Rate of Rise)
Geophysics & Environmental Physics

Seafloor Spreading

The tectonic process occurring at mid-ocean ridges where new oceanic crust is created by upwelling mantle magma and moves laterally away.

Spreading Rate v = d / t ~ 2–16 cm/year cm/year (Spreading Rate)
Thermodynamics & Statistical Physics

Second Law of Thermodynamics

The law asserting that spontaneous physical processes increase total entropy in isolated systems, placing fundamental limits on heat engine…

ΔS_total ≥ 0 J/K