D | Glossary of Key Symbols

D | Glossary of Key Symbols

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

Symbol Definition
any symbol¯any symbol¯ size 12{ {overline {"any"`" symbol"}} } {} average (indicated by a bar over a symbol—e.g., v¯v¯ size 12{ {overline {v}} } {} is average velocity)
°C°C size 12{°C} {} Celsius degree
°F°F size 12{°F} {} Fahrenheit degree
//// size 12{"//"} {} parallel
size 12{ ortho } {} perpendicular
size 12{ prop } {} proportional to
±± size 12{ +- {}} {} plus or minus
00 size 12{ {} rSub { size 8{0} } } {} zero as a subscript denotes an initial value
αα size 12{α} {} alpha rays
αα size 12{α} {} angular acceleration
αα size 12{α} {} temperature coefficient(s) of resistivity
ββ size 12{β} {} beta rays
ββ size 12{β} {} sound level
ββ size 12{β} {} volume coefficient of expansion
ββ size 12{β rSup { size 8{ - {}} } } {} electron emitted in nuclear beta decay
β+β+ size 12{β rSup { size 8{+{}} } } {} positron decay
γγ size 12{γ} {} gamma rays
γγ size 12{γ} {} surface tension
γ=1/1v2/c2γ=1/1v2/c2 size 12{γ= {1} slash { sqrt {1 - {v rSup { size 8{2} } } slash {c rSup { size 8{2} } } } } } {} a constant used in relativity
ΔΔ size 12{Δ} {} change in whatever quantity follows
δδ size 12{δ} {} uncertainty in whatever quantity follows
ΔEΔE size 12{ΔE} {} change in energy between the initial and final orbits of an electron in an atom
ΔEΔE size 12{ΔE} {} uncertainty in energy
ΔmΔm size 12{Δm} {} difference in mass between initial and final products
ΔNΔN size 12{ΔN} {} number of decays that occur
ΔpΔp size 12{Δp} {} change in momentum
ΔpΔp size 12{Δp} {} uncertainty in momentum
ΔPEgΔPEg size 12{Δ"PE" rSub { size 8{g} } } {} change in gravitational potential energy
ΔθΔθ size 12{Δθ} {} rotation angle
ΔsΔs size 12{Δs} {} distance traveled along a circular path
ΔtΔt size 12{Δt} {} uncertainty in time
Δt0Δt0 size 12{Δt rSub { size 8{0} } } {} proper time as measured by an observer at rest relative to the process
ΔVΔV size 12{ΔV} {} potential difference
ΔxΔx size 12{Δx} {} uncertainty in position
ε0ε0 size 12{ε rSub { size 8{0} } } {} permittivity of free space
ηη size 12{η} {} viscosity
θθ size 12{θ} {} angle between the force vector and the displacement vector
θθ size 12{θ} {} angle between two lines
θθ size 12{θ} {} contact angle
θθ size 12{θ} {} direction of the resultant
θbθb size 12{θ rSub { size 8{b} } } {} Brewster's angle
θcθc size 12{θ rSub { size 8{c} } } {} critical angle
κκ size 12{κ} {} dielectric constant
λλ size 12{λ} {} decay constant of a nuclide
λλ size 12{λ} {} wavelength
λnλn size 12{λ rSub { size 8{n} } } {} wavelength in a medium
μ0μ0 size 12{μ rSub { size 8{0} } } {} permeability of free space
μkμk size 12{μ rSub { size 8{k} } } {} coefficient of kinetic friction
μsμs size 12{μ rSub { size 8{s} } } {} coefficient of static friction
veve size 12{v rSub { size 8{e} } } {} electron neutrino
π+π+ size 12{π rSup { size 8{+{}} } } {} positive pion
ππ size 12{π rSup { size 8{ - {}} } } {} negative pion
π0π0 size 12{π rSup { size 8{0} } } {} neutral pion
ρρ size 12{ρ} {} density
ρcρc size 12{ρ rSub { size 8{c} } } {} critical density, the density needed to just halt universal expansion
ρflρfl size 12{ρ rSub { size 8{"fl"} } } {} fluid density
ρ¯objρ¯obj size 12{ {overline {ρ}} rSub { size 8{"obj"} } } {} average density of an object
ρ/ρwρ/ρw size 12{ {ρ} slash {ρ rSub { size 8{w} } } } {} specific gravity
ττ size 12{τ} {} characteristic time constant for a resistance and inductance (RL)(RL) size 12{ \( ital "RL" \) } {} or resistance and capacitance (RC)(RC) size 12{ \( ital "RC" \) } {} circuit
ττ size 12{τ} {} characteristic time for a resistor and capacitor (RC)(RC) size 12{ \( ital "RC" \) } {} circuit
ττ size 12{τ} {} torque
ΥΥ size 12{Υ} {} upsilon meson
ΦΦ size 12{Φ} {} magnetic flux
ϕϕ size 12{ϕ} {} phase angle
ΩΩ size 12{ %OMEGA } {} ohm (unit)
ωω size 12{ω} {} angular velocity
AA size 12{A} {} ampere (current unit)
AA size 12{A} {} area
AA size 12{A} {} cross-sectional area
AA size 12{A} {} total number of nucleons
aa size 12{a} {} acceleration
aBaB size 12{a rSub { size 8{B} } } {} Bohr radius
acac size 12{a rSub { size 8{c} } } {} centripetal acceleration
atat size 12{a rSub { size 8{t} } } {} tangential acceleration
ACAC size 12{"AC"} {} alternating current
AMAM size 12{"AM"} {} amplitude modulation
atmatm size 12{"atm"} {} atmosphere
BB size 12{B} {} baryon number
BB size 12{B} {} blue quark color
B¯B¯ size 12{ {overline {B}} } {} antiblue (yellow) antiquark color
bb size 12{b} {} quark flavor bottom or beauty
BB size 12{B} {} bulk modulus
BB size 12{B} {} magnetic field strength
BintBint size 12{B rSub { size 8{"int"} } } {} electron’s intrinsic magnetic field
BorbBorb size 12{B rSub { size 8{"orb"} } } {} orbital magnetic field
BEBE size 12{"BE"} {} binding energy of a nucleus—it is the energy required to completely disassemble it into separate protons and neutrons
BE/ABE/A size 12{ {"BE"} slash {A} } {} binding energy per nucleon
BqBq size 12{"Bq"} {} becquerel—one decay per second
CC size 12{C} {} capacitance (amount of charge stored per volt)
CC size 12{C} {} coulomb (a fundamental SI unit of charge)
CpCp size 12{C rSub { size 8{p} } } {} total capacitance in parallel
CsCs size 12{C rSub { size 8{s} } } {} total capacitance in series
CGCG size 12{"CG"} {} center of gravity
CMCM size 12{"CM"} {} center of mass
cc size 12{c} {} quark flavor charm
cc size 12{c} {} specific heat
cc size 12{c} {} speed of light
CalCal size 12{"Cal"} {} kilocalorie
calcal size 12{"cal"} {} calorie
COPhpCOPhp size 12{ ital "COP" rSub { size 8{"hp"} } } {} heat pump’s coefficient of performance
COPrefCOPref size 12{ ital "COP" rSub { size 8{"ref"} } } {} coefficient of performance for refrigerators and air conditioners
cosθcosθ size 12{"cos"θ} {} cosine
cotθcotθ size 12{"cot"θ} {} cotangent
cscθcscθ size 12{"csc"θ} {} cosecant
DD size 12{D} {} diffusion constant
dd size 12{d} {} displacement
dd size 12{d} {} quark flavor down
dBdB size 12{"dB"} {} decibel
didi size 12{d rSub { size 8{i} } } {} distance of an image from the center of a lens
dodo size 12{d rSub { size 8{o} } } {} distance of an object from the center of a lens
DCDC size 12{"DC"} {} direct current
EE size 12{E} {} electric field strength
εε size 12{ε} {} emf (voltage) or Hall electromotive force
emfemf size 12{"emf"} {} electromotive force
EE size 12{E} {} energy of a single photon
EE size 12{E} {} nuclear reaction energy
EE size 12{E} {} relativistic total energy
EE size 12{E} {} total energy
E0E0 size 12{E rSub { size 8{0} } } {} ground state energy for hydrogen
E0E0 size 12{E rSub { size 8{0} } } {} rest energy
ECEC size 12{"EC"} {} electron capture
EcapEcap size 12{E rSub { size 8{"cap"} } } {} energy stored in a capacitor
EffEff size 12{ ital "Eff"} {} efficiency—the useful work output divided by the energy input
EffCEffC size 12{ ital "Eff" rSub { size 8{C} } } {} Carnot efficiency
EinEin size 12{E rSub { size 8{"in"} } } {} energy consumed (food digested in humans)
EindEind size 12{E rSub { size 8{"ind"} } } {} energy stored in an inductor
EoutEout size 12{E rSub { size 8{"out"} } } {} energy output
ee size 12{e} {} emissivity of an object
e+e+ size 12{e rSup { size 8{+{}} } } {} antielectron or positron
eVeV size 12{"eV"} {} electron volt
FF size 12{F} {} farad (unit of capacitance, a coulomb per volt)
FF size 12{F} {} focal point of a lens
FF size 12{F} {} force
FF size 12{F} {} magnitude of a force
FF size 12{F} {} restoring force
FBFB size 12{F rSub { size 8{B} } } {} buoyant force
FcFc size 12{F rSub { size 8{c} } } {} centripetal force
FiFi size 12{F rSub { size 8{i} } } {} force input
FnetFnet size 12{F rSub { size 8{"net"} } } {} net force
FoFo size 12{F rSub { size 8{o} } } {} force output
FMFM size 12{"FM"} {} frequency modulation
ff size 12{f} {} focal length
ff size 12{f} {} frequency
f0f0 size 12{f rSub { size 8{0} } } {} resonant frequency of a resistance, inductance, and capacitance (RLC)(RLC) size 12{ \( ital "RLC" \) } {} series circuit
f0f0 size 12{f rSub { size 8{0} } } {} threshold frequency for a particular material (photoelectric effect)
f1f1 size 12{f rSub { size 8{1} } } {} fundamental
f2f2 size 12{f rSub { size 8{2} } } {} first overtone
f3f3 size 12{f rSub { size 8{3} } } {} second overtone
fBfB size 12{f rSub { size 8{B} } } {} beat frequency
fkfk size 12{f rSub { size 8{k} } } {} magnitude of kinetic friction
fsfs size 12{f rSub { size 8{s} } } {} magnitude of static friction
GG size 12{G} {} gravitational constant
GG size 12{G} {} green quark color
G¯G¯ size 12{ {overline {G}} } {} antigreen (magenta) antiquark color
gg size 12{g} {} acceleration due to gravity
gg size 12{g} {} gluons (carrier particles for strong nuclear force)
hh size 12{h} {} change in vertical position
hh size 12{h} {} height above some reference point
hh size 12{h} {} maximum height of a projectile
hh size 12{h} {} Planck's constant
hfhf size 12{ ital "hf"} {} photon energy
hihi size 12{h rSub { size 8{i} } } {} height of the image
hoho size 12{h rSub { size 8{o} } } {} height of the object
II size 12{I} {} electric current
II size 12{I} {} intensity
II size 12{I} {} intensity of a transmitted wave
II size 12{I} {} moment of inertia (also called rotational inertia)
I0I0 size 12{I rSub { size 8{0} } } {} intensity of a polarized wave before passing through a filter
IaveIave size 12{I rSub { size 8{"ave"} } } {} average intensity for a continuous sinusoidal electromagnetic wave
IrmsIrms size 12{I rSub { size 8{"rms"} } } {} average current
JJ size 12{J} {} joule
J/ΨJ/Ψ size 12{ {J} slash {Ψ} } {} Joules/psi meson
KK size 12{K} {} kelvin
kk size 12{k} {} Boltzmann constant
kk size 12{k} {} force constant of a spring
KαKα size 12{K rSub { size 8{α} } } {} x rays created when an electron falls into an n=1n=1 size 12{n=1} {} shell vacancy from the n=3n=3 size 12{n=3} {} shell
KβKβ size 12{K rSub { size 8{β} } } {} x rays created when an electron falls into an n=2n=2 size 12{n=2} {} shell vacancy from the n=3n=3 size 12{n=3} {} shell
kcalkcal size 12{"kcal"} {} kilocalorie
KEKE size 12{"KE"} {} translational kinetic energy
KE + PEKE + PE size 12{"KE"+" PE"} {} mechanical energy
KEeKEe size 12{"KE" rSub { size 8{e} } } {} kinetic energy of an ejected electron
KErelKErel size 12{"KE" rSub { size 8{"rel"} } } {} relativistic kinetic energy
KErotKErot size 12{"KE" rSub { size 8{"rot"} } } {} rotational kinetic energy
KE¯KE¯ size 12{ {overline {"KE"}} } {} thermal energy
kgkg size 12{"kg"} {} kilogram (a fundamental SI unit of mass)
LL size 12{L} {} angular momentum
LL size 12{L} {} liter
LL size 12{L} {} magnitude of angular momentum
LL size 12{L} {} self-inductance
size 12{ℓ} {} angular momentum quantum number
LαLα size 12{L rSub { size 8{α} } } {} x rays created when an electron falls into an n=2n=2 size 12{n=2} {} shell from the n=3n=3 size 12{n=3} {} shell
LeLe size 12{L rSub { size 8{e} } } {} electron total family number
LμLμ size 12{L rSub { size 8{μ} } } {} muon family total number
LτLτ size 12{L rSub { size 8{τ} } } {} tau family total number
LfLf size 12{L rSub { size 8{f} } } {} heat of fusion
Lf andLvLf andLv size 12{L rSub { size 8{f} } " and"` L rSub { size 8{v} } } {} latent heat coefficients
LorbLorb size 12{L rSub { size 8{"orb"} } } {} orbital angular momentum
LsLs size 12{L rSub { size 8{s} } } {} heat of sublimation
LvLv size 12{L rSub { size 8{v} } } {} heat of vaporization
LzLz size 12{L rSub { size 8{z} } } {} z - component of the angular momentum
MM size 12{M} {} angular magnification
MM size 12{M} {} mutual inductance
mm size 12{m} {} indicates metastable state
mm size 12{m} {} magnification
mm size 12{m} {} mass
mm size 12{m} {} mass of an object as measured by a person at rest relative to the object
mm size 12{m} {} meter (a fundamental SI unit of length)
mm size 12{m} {} order of interference
mm size 12{m} {} overall magnification (product of the individual magnifications)
mAXmAX size 12{m left ("" lSup { size 8{A} } X right )} {} atomic mass of a nuclide
MAMA size 12{"MA"} {} mechanical advantage
meme size 12{m rSub { size 8{e} } } {} magnification of the eyepiece
meme size 12{m rSub { size 8{e} } } {} mass of the electron
mm size 12{m rSub { size 8{ℓ} } } {} angular momentum projection quantum number
mnmn size 12{m rSub { size 8{n} } } {} mass of a neutron
momo size 12{m rSub { size 8{o} } } {} magnification of the objective lens
molmol size 12{"mol"} {} mole
mpmp size 12{m rSub { size 8{p} } } {} mass of a proton
msms size 12{m rSub { size 8{s} } } {} spin projection quantum number
NN size 12{N} {} magnitude of the normal force
NN size 12{N} {} newton
NN size 12{N} {} normal force
NN size 12{N} {} number of neutrons
nn size 12{n} {} index of refraction
nn size 12{n} {} number of free charges per unit volume
NANA size 12{N rSub { size 8{A} } } {} Avogadro's number
NrNr size 12{N rSub { size 8{r} } } {} Reynolds number
NmNm size 12{N cdot m} {} newton-meter (work-energy unit)
NmNm size 12{N cdot m} {} newtons times meters (SI unit of torque)
OEOE size 12{"OE"} {} other energy
PP size 12{P} {} power
PP size 12{P} {} power of a lens
PP size 12{P} {} pressure
pp size 12{p} {} momentum
pp size 12{p} {} momentum magnitude
pp size 12{p} {} relativistic momentum
ptotptot size 12{p rSub { size 8{"tot"} } } {} total momentum
ptot'ptot' size 12{ { {p}} sup { ' } rSub { size 8{`"tot"} } } {} total momentum some time later
PabsPabs size 12{P rSub { size 8{"abs"} } } {} absolute pressure
PatmPatm size 12{P rSub { size 8{"atm"} } } {} atmospheric pressure
PatmPatm size 12{P rSub { size 8{"atm"} } } {} standard atmospheric pressure
PEPE size 12{"PE"} {} potential energy
PEelPEel size 12{"PE" rSub { size 8{"el"} } } {} elastic potential energy
PEelecPEelec size 12{"PE" rSub { size 8{"elec"} } } {} electric potential energy
PEsPEs size 12{"PE" rSub { size 8{s} } } {} potential energy of a spring
PgPg size 12{P rSub { size 8{g} } } {} gauge pressure
PinPin size 12{P rSub { size 8{"in"} } } {} power consumption or input
PoutPout size 12{P rSub { size 8{"out"} } } {} useful power output going into useful work or a desired, form of energy
QQ size 12{Q} {} latent heat
QQ size 12{Q} {} net heat transferred into a system
QQ size 12{Q} {} flow rate—volume per unit time flowing past a point
+Q+Q size 12{+Q} {} positive charge
QQ size 12{ - Q} {} negative charge
qq size 12{q} {} electron charge
qpqp size 12{q rSub { size 8{p} } } {} charge of a proton
qq size 12{q} {} test charge
QFQF size 12{"QF"} {} quality factor
RR size 12{R} {} activity, the rate of decay
RR size 12{R} {} radius of curvature of a spherical mirror
RR size 12{R} {} red quark color
R¯R¯ size 12{ {overline {R}} } {} antired (cyan) quark color
RR size 12{R} {} resistance
RR size 12{R} {} resultant or total displacement
RR size 12{R} {} Rydberg constant
RR size 12{R} {} universal gas constant
rr size 12{r} {} distance from pivot point to the point where a force is applied
rr size 12{r} {} internal resistance
rr size 12{r rSub { size 8{ ortho } } } {} perpendicular lever arm
rr size 12{r} {} radius of a nucleus
rr size 12{r} {} radius of curvature
rr size 12{r} {} resistivity
r or radr or rad size 12{"r or rad"} {} radiation dose unit
remrem size 12{"rem"} {} roentgen equivalent man
radrad size 12{"rad"} {} radian
RBERBE size 12{"RBE"} {} relative biological effectiveness
RCRC size 12{ ital "RC"} {} resistor and capacitor circuit
rmsrms size 12{"rms"} {} root mean square
rnrn size 12{r rSub { size 8{n} } } {} radius of the nth H-atom orbit
RpRp size 12{R rSub { size 8{p} } } {} total resistance of a parallel connection
RsRs size 12{R rSub { size 8{s} } } {} total resistance of a series connection
RsRs size 12{R rSub { size 8{s} } } {} Schwarzschild radius
SS size 12{S} {} entropy
SS size 12{S} {} intrinsic spin (intrinsic angular momentum)
SS size 12{S} {} magnitude of the intrinsic (internal) spin angular momentum
SS size 12{S} {} shear modulus
SS size 12{S} {} strangeness quantum number
ss size 12{s} {} quark flavor strange
ss size 12{s} {} second (fundamental SI unit of time)
ss size 12{s} {} spin quantum number
ss size 12{s} {} total displacement
secθsecθ size 12{"sec"θ} {} secant
sinθsinθ size 12{"sin"θ} {} sine
szsz size 12{s rSub { size 8{z} } } {} z-component of spin angular momentum
TT size 12{T} {} period—time to complete one oscillation
TT size 12{T} {} temperature
TcTc size 12{T rSub { size 8{c} } } {} critical temperature—temperature below which a material becomes a superconductor
TT size 12{T} {} tension
TT size 12{T} {} tesla (magnetic field strength B)
tt size 12{t} {} quark flavor top or truth
tt size 12{t} {} time
t1/2t1/2 size 12{t rSub { size 8{ {1} slash {2} } } } {} half-life—the time in which half of the original nuclei decay
tanθtanθ size 12{"tan"θ} {} tangent
UU size 12{U} {} internal energy
uu size 12{u} {} quark flavor up
uu size 12{u} {} unified atomic mass unit
uu size 12{u} {} velocity of an object relative to an observer
u'u' size 12{ { {u}} sup { ' }} {} velocity relative to another observer
VV size 12{V} {} electric potential
VV size 12{V} {} terminal voltage
VV size 12{V} {} volt (unit)
VV size 12{V} {} volume
vv size 12{v} {} relative velocity between two observers
vv size 12{v} {} speed of light in a material
vv size 12{v} {} velocity
v¯v¯ size 12{ {overline {v}} } {} average fluid velocity
VBVAVBVA size 12{V rSub { size 8{B} } - V rSub { size 8{A} } } {} change in potential
vdvd size 12{v rSub { size 8{d} } } {} drift velocity
VpVp size 12{V rSub { size 8{p} } } {} transformer input voltage
VrmsVrms size 12{V rSub { size 8{"rms"} } } {} rms voltage
VsVs size 12{V rSub { size 8{s} } } {} transformer output voltage
vtotvtot size 12{v rSub { size 8{"tot"} } } {} total velocity
vwvw size 12{v rSub { size 8{w} } } {} propagation speed of sound or other wave
vwvw size 12{v rSub { size 8{w} } } {} wave velocity
WW size 12{W} {} work
WW size 12{W} {} net work done by a system
WW size 12{W} {} watt
ww size 12{w} {} weight
wflwfl size 12{w rSub { size 8{"fl"} } } {} weight of the fluid displaced by an object
WcWc size 12{W rSub { size 8{c} } } {} total work done by all conservative forces
WncWnc size 12{W rSub { size 8{"nc"} } } {} total work done by all nonconservative forces
WoutWout size 12{W rSub { size 8{"out"} } } {} useful work output
XX size 12{X} {} amplitude
XX size 12{X} {} symbol for an element
ZAXNZAXN size 12{"" lSub { size 8{Z} } lSup { size 8{A} } X rSub { size 8{N} } } {} notation for a particular nuclide
xx size 12{x} {} deformation or displacement from equilibrium
xx size 12{x} {} displacement of a spring from its undeformed position
xx size 12{x} {} horizontal axis
XCXC size 12{X rSub { size 8{C} } } {} capacitive reactance
XLXL size 12{X rSub { size 8{L} } } {} inductive reactance
xrmsxrms size 12{x rSub { size 8{"rms"} } } {} root mean square diffusion distance
yy size 12{y} {} vertical axis
YY size 12{Y} {} elastic modulus or Young's modulus
ZZ size 12{Z} {} atomic number (number of protons in a nucleus)
ZZ size 12{Z} {} impedance
Table D1