Gregg Wolfe; Erika Gasper; John Stoke; Julie Kretchman; David Anderson; Nathan Czuba; Sudhi Oberoi; Liza Pujji; Irina Lyublinskaya; Douglas Ingram

In this glossary, key symbols and notation are briefly defined.

Symbol	Definition
$\bar{any symbol}$	average (indicated by a bar over a symbol—e.g., $\bar{v}$ is average velocity)
$° C$	Celsius degree
$° F$	Fahrenheit degree
$//$	parallel
$⊥$	perpendicular
$\propto$	proportional to
$\pm$	plus or minus
$_{0}$	zero as a subscript denotes an initial value
$α$	alpha rays
$α$	angular acceleration
$α$	temperature coefficient(s) of resistivity
$β$	beta rays
$β$	sound level
$β$	volume coefficient of expansion
$β^{-}$	electron emitted in nuclear beta decay
$β^{+}$	positron decay
$γ$	gamma rays
$γ$	surface tension
$γ = 1 / \sqrt{1 - v^{2} / c^{2}}$	a constant used in relativity
$Δ$	change in whatever quantity follows
$δ$	uncertainty in whatever quantity follows
$ΔE$	change in energy between the initial and final orbits of an electron in an atom
$ΔE$	uncertainty in energy
$Δm$	difference in mass between initial and final products
$ΔN$	number of decays that occur
$Δp$	change in momentum
$Δp$	uncertainty in momentum
$Δ {PE}_{g}$	change in gravitational potential energy
$Δθ$	rotation angle
$Δs$	distance traveled along a circular path
$Δt$	uncertainty in time
${Δt}_{0}$	proper time as measured by an observer at rest relative to the process
$ΔV$	potential difference
$Δx$	uncertainty in position
$ε_{0}$	permittivity of free space
$η$	viscosity
$θ$	angle between the force vector and the displacement vector
$θ$	angle between two lines
$θ$	contact angle
$θ$	direction of the resultant
$θ_{b}$	Brewster's angle
$θ_{c}$	critical angle
$κ$	dielectric constant
$λ$	decay constant of a nuclide
$λ$	wavelength
$λ_{n}$	wavelength in a medium
$μ_{0}$	permeability of free space
$μ_{k}$	coefficient of kinetic friction
$μ_{s}$	coefficient of static friction
$v_{e}$	electron neutrino
$π^{+}$	positive pion
$π^{-}$	negative pion
$π^{0}$	neutral pion
$ρ$	density
$ρ_{c}$	critical density, the density needed to just halt universal expansion
$ρ_{fl}$	fluid density
${\bar{ρ}}_{obj}$	average density of an object
$ρ / ρ_{w}$	specific gravity
$τ$	characteristic time constant for a resistance and inductance $(RL)$ or resistance and capacitance $(RC)$ circuit
$τ$	characteristic time for a resistor and capacitor $(RC)$ circuit
$τ$	torque
$Υ$	upsilon meson
$Φ$	magnetic flux
$ϕ$	phase angle
$Ω$	ohm (unit)
$ω$	angular velocity
$A$	ampere (current unit)
$A$	area
$A$	cross-sectional area
$A$	total number of nucleons
$a$	acceleration
$a_{B}$	Bohr radius
$a_{c}$	centripetal acceleration
$a_{t}$	tangential acceleration
$AC$	alternating current
$AM$	amplitude modulation
$atm$	atmosphere
$B$	baryon number
$B$	blue quark color
$\bar{B}$	antiblue (yellow) antiquark color
$b$	quark flavor bottom or beauty
$B$	bulk modulus
$B$	magnetic field strength
$B_{int}$	electron’s intrinsic magnetic field
$B_{orb}$	orbital magnetic field
$BE$	binding energy of a nucleus—it is the energy required to completely disassemble it into separate protons and neutrons
$BE / A$	binding energy per nucleon
$Bq$	becquerel—one decay per second
$C$	capacitance (amount of charge stored per volt)
$C$	coulomb (a fundamental SI unit of charge)
$C_{p}$	total capacitance in parallel
$C_{s}$	total capacitance in series
$CG$	center of gravity
$CM$	center of mass
$c$	quark flavor charm
$c$	specific heat
$c$	speed of light
$Cal$	kilocalorie
$cal$	calorie
${COP}_{hp}$	heat pump’s coefficient of performance
${COP}_{ref}$	coefficient of performance for refrigerators and air conditioners
$cos θ$	cosine
$cot θ$	cotangent
$csc θ$	cosecant
$D$	diffusion constant
$d$	displacement
$d$	quark flavor down
$dB$	decibel
$d_{i}$	distance of an image from the center of a lens
$d_{o}$	distance of an object from the center of a lens
$DC$	direct current
$E$	electric field strength
$ε$	emf (voltage) or Hall electromotive force
$emf$	electromotive force
$E$	energy of a single photon
$E$	nuclear reaction energy
$E$	relativistic total energy
$E$	total energy
$E_{0}$	ground state energy for hydrogen
$E_{0}$	rest energy
$EC$	electron capture
$E_{cap}$	energy stored in a capacitor
$Eff$	efficiency—the useful work output divided by the energy input
${Eff}_{C}$	Carnot efficiency
$E_{in}$	energy consumed (food digested in humans)
$E_{ind}$	energy stored in an inductor
$E_{out}$	energy output
$e$	emissivity of an object
$e^{+}$	antielectron or positron
$eV$	electron volt
$F$	farad (unit of capacitance, a coulomb per volt)
$F$	focal point of a lens
$F$	force
$F$	magnitude of a force
$F$	restoring force
$F_{B}$	buoyant force
$F_{c}$	centripetal force
$F_{i}$	force input
$F_{net}$	net force
$F_{o}$	force output
$FM$	frequency modulation
$f$	focal length
$f$	frequency
$f_{0}$	resonant frequency of a resistance, inductance, and capacitance $(RLC)$ series circuit
$f_{0}$	threshold frequency for a particular material (photoelectric effect)
$f_{1}$	fundamental
$f_{2}$	first overtone
$f_{3}$	second overtone
$f_{B}$	beat frequency
$f_{k}$	magnitude of kinetic friction
$f_{s}$	magnitude of static friction
$G$	gravitational constant
$G$	green quark color
$\bar{G}$	antigreen (magenta) antiquark color
$g$	acceleration due to gravity
$g$	gluons (carrier particles for strong nuclear force)
$h$	change in vertical position
$h$	height above some reference point
$h$	maximum height of a projectile
$h$	Planck's constant
$hf$	photon energy
$h_{i}$	height of the image
$h_{o}$	height of the object
$I$	electric current
$I$	intensity
$I$	intensity of a transmitted wave
$I$	moment of inertia (also called rotational inertia)
$I_{0}$	intensity of a polarized wave before passing through a filter
$I_{ave}$	average intensity for a continuous sinusoidal electromagnetic wave
$I_{rms}$	average current
$J$	joule
$J / Ψ$	Joules/psi meson
$K$	kelvin
$k$	Boltzmann constant
$k$	force constant of a spring
$K_{α}$	x rays created when an electron falls into an $n = 1$ shell vacancy from the $n = 3$ shell
$K_{β}$	x rays created when an electron falls into an $n = 2$ shell vacancy from the $n = 3$ shell
$kcal$	kilocalorie
$KE$	translational kinetic energy
$KE + PE$	mechanical energy
${KE}_{e}$	kinetic energy of an ejected electron
${KE}_{rel}$	relativistic kinetic energy
${KE}_{rot}$	rotational kinetic energy
$\bar{KE}$	thermal energy
$kg$	kilogram (a fundamental SI unit of mass)
$L$	angular momentum
$L$	liter
$L$	magnitude of angular momentum
$L$	self-inductance
$ℓ$	angular momentum quantum number
$L_{α}$	x rays created when an electron falls into an $n = 2$ shell
$L_{e}$	electron total family number
$L_{μ}$	muon family total number
$L_{τ}$	tau family total number
$L_{f}$	heat of fusion
$L_{f} and L_{v}$	latent heat coefficients
$L_{orb}$	orbital angular momentum
$L_{s}$	heat of sublimation
$L_{v}$	heat of vaporization
$L_{z}$	z - component of the angular momentum
$M$	angular magnification
$M$	mutual inductance
$m$	indicates metastable state
$m$	magnification
$m$	mass
$m$	mass of an object as measured by a person at rest relative to the object
$m$	meter (a fundamental SI unit of length)
$m$	order of interference
$m$	overall magnification (product of the individual magnifications)
$m (^{A} X)$	atomic mass of a nuclide
$MA$	mechanical advantage
$m_{e}$	magnification of the eyepiece
$m_{e}$	mass of the electron
$m_{ℓ}$	angular momentum projection quantum number
$m_{n}$	mass of a neutron
$m_{o}$	magnification of the objective lens
$mol$	mole
$m_{p}$	mass of a proton
$m_{s}$	spin projection quantum number
$N$	magnitude of the normal force
$N$	newton
$N$	normal force
$N$	number of neutrons
$n$	index of refraction
$n$	number of free charges per unit volume
$N_{A}$	Avogadro's number
$N_{r}$	Reynolds number
$N \cdot m$	newton-meter (work-energy unit)
$N \cdot m$	newtons times meters (SI unit of torque)
$OE$	other energy
$P$	power
$P$	power of a lens
$P$	pressure
$p$	momentum
$p$	momentum magnitude
$p$	relativistic momentum
$p_{tot}$	total momentum
$p_{tot}^{'}$	total momentum some time later
$P_{abs}$	absolute pressure
$P_{atm}$	atmospheric pressure
$P_{atm}$	standard atmospheric pressure
$PE$	potential energy
${PE}_{el}$	elastic potential energy
${PE}_{elec}$	electric potential energy
${PE}_{s}$	potential energy of a spring
$P_{g}$	gauge pressure
$P_{in}$	power consumption or input
$P_{out}$	useful power output going into useful work or a desired, form of energy
$Q$	latent heat
$Q$	net heat transferred into a system
$Q$	flow rate—volume per unit time flowing past a point
$+ Q$	positive charge
$- Q$	negative charge
$q$	electron charge
$q_{p}$	charge of a proton
$q$	test charge
$QF$	quality factor
$R$	activity, the rate of decay
$R$	radius of curvature of a spherical mirror
$R$	red quark color
$\bar{R}$	antired (cyan) quark color
$R$	resistance
$R$	resultant or total displacement
$R$	Rydberg constant
$R$	universal gas constant
$r$	distance from pivot point to the point where a force is applied
$r$	internal resistance
$r_{⊥}$	perpendicular lever arm
$r$	radius of a nucleus
$r$	radius of curvature
$r$	resistivity
$r or rad$	radiation dose unit
$rem$	roentgen equivalent man
$rad$	radian
$RBE$	relative biological effectiveness
$RC$	resistor and capacitor circuit
$rms$	root mean square
$r_{n}$	radius of the nth H-atom orbit
$R_{p}$	total resistance of a parallel connection
$R_{s}$	total resistance of a series connection
$R_{s}$	Schwarzschild radius
$S$	entropy
$S$	intrinsic spin (intrinsic angular momentum)
$S$	magnitude of the intrinsic (internal) spin angular momentum
$S$	shear modulus
$S$	strangeness quantum number
$s$	quark flavor strange
$s$	second (fundamental SI unit of time)
$s$	spin quantum number
$s$	total displacement
$sec θ$	secant
$sin θ$	sine
$s_{z}$	z-component of spin angular momentum
$T$	period—time to complete one oscillation
$T$	temperature
$T_{c}$	critical temperature—temperature below which a material becomes a superconductor
$T$	tension
$T$	tesla (magnetic field strength B)
$t$	quark flavor top or truth
$t$	time
$t_{1 / 2}$	half-life—the time in which half of the original nuclei decay
$tan θ$	tangent
$U$	internal energy
$u$	quark flavor up
$u$	unified atomic mass unit
$u$	velocity of an object relative to an observer
$u^{'}$	velocity relative to another observer
$V$	electric potential
$V$	terminal voltage
$V$	volt (unit)
$V$	volume
$v$	relative velocity between two observers
$v$	speed of light in a material
$v$	velocity
$\bar{v}$	average fluid velocity
$V_{B} - V_{A}$	change in potential
$v_{d}$	drift velocity
$V_{p}$	transformer input voltage
$V_{rms}$	rms voltage
$V_{s}$	transformer output voltage
$v_{tot}$	total velocity
$v_{w}$	propagation speed of sound or other wave
$v_{w}$	wave velocity
$W$	work
$W$	net work done by a system
$W$	watt
$w$	weight
$w_{fl}$	weight of the fluid displaced by an object
$W_{c}$	total work done by all conservative forces
$W_{nc}$	total work done by all nonconservative forces
$W_{out}$	useful work output
$X$	amplitude
$X$	symbol for an element
$_{A}^{Z} X_{N}$	notation for a particular nuclide
$x$	deformation or displacement from equilibrium
$x$	displacement of a spring from its undeformed position
$x$	horizontal axis
$X_{C}$	capacitive reactance
$X_{L}$	inductive reactance
$x_{rms}$	root mean square diffusion distance
$y$	vertical axis
$Y$	elastic modulus or Young's modulus
$Z$	atomic number (number of protons in a nucleus)
$Z$	impedance

Table D1

D | Glossary of Key Symbols and Notation