| \(\overline{\text { any symbol }}\) | average (indicated by a bar over a symbol—e.g., \(\bar{v}\) is average velocity) |
| \({ }^{\circ} \mathrm{C}\) | Celsius degree |
| \({ }^{\circ} \mathrm{F}\) | Fahrenheit degree |
| \(\text { // }\) | parallel |
| \(\perp\) | perpendicular |
| \(\propto\) | proportional to |
| \(\pm\) | plus or minus |
| \(0\) | zero as a subscript denotes an initial value |
| \(\alpha\) | alpha rays |
| \(\alpha\) | angular acceleration |
| \(\alpha\) | temperature coefficient(s) of resistivity |
| \(\beta\) | beta rays |
| \(\beta\) | sound level |
| \(\beta\) | volume coefficient of expansion |
| \(\beta^{-}\) | electron emitted in nuclear beta decay |
| \(\beta^{+}\) | positron decay |
| \(\gamma\) | gamma rays |
| \(\gamma\) | surface tension |
| \(\gamma=1 / \sqrt{1-v^{2} / c^{2}}\) | a constant used in relativity |
| \(\Delta\) | change in whatever quantity follows |
| \(\delta\) | uncertainty in whatever quantity follows |
| \(\Delta E\) | change in energy between the initial and final orbits of an electron in an atom |
| \(\Delta E\) | uncertainty in energy |
| \(\Delta m\) | difference in mass between initial and final products |
| \(\Delta N\) | number of decays that occur |
| \(\Delta p\) | change in momentum |
| \(\Delta p\) | uncertainty in momentum |
| \(\Delta \mathrm{PE}_{\mathrm{g}}\) | change in gravitational potential energy |
| \(\Delta \theta\) | rotation angle |
| \(\Delta s\) | distance traveled along a circular path |
| \(\Delta t\) | uncertainty in time |
| \(\Delta t_{0}\) | proper time as measured by an observer at rest relative to the process |
| \(\Delta V\) | potential difference |
| \(\Delta x\) | uncertainty in position |
| \(\varepsilon_{0}\) | permittivity of free space |
| \(\eta\) | viscosity |
| \(\theta\) | angle between the force vector and the displacement vector |
| \(\theta\) | angle between two lines |
| \(\theta\) | contact angle |
| \(\theta\) | direction of the resultant |
| \(\theta_{b}\) | Brewster's angle |
| \(\theta_{c}\) | critical angle |
| \(\kappa\) | dielectric constant |
| \(\lambda\) | decay constant of a nuclide |
| \(\lambda\) | wavelength |
| \(\lambda_{n}\) | wavelength in a medium |
| \(\mu_{0}\) | permeability of free space |
| \(\mu_{\mathrm{k}}\) | coefficient of kinetic friction |
| \(\mu_{\mathrm{s}}\) | coefficient of static friction |
| \(v_{e}\) | electron neutrino |
| \(\pi^{+}\) | positive pion |
| \(\pi^{-}\) | negative pion |
| \(\pi^{0}\) | neutral pion |
| \(\rho\) | density |
| \(\rho_{\mathrm{c}}\) | critical density, the density needed to just halt universal expansion |
| \(\rho_{\mathrm{fl}}\) | fluid density |
| \(\bar{\rho}_{\text {obj }}\) | average density of an object |
| \(\rho / \rho_{\mathrm{w}}\) | specific gravity |
| \(\tau\) | characteristic time constant for a resistance and inductance \((R L)\) or resistance and capacitance \((R C)\) circuit |
| \(\tau\) | characteristic time for a resistor and capacitor \((R C)\) circuit |
| \(\tau\) | torque |
| \(\Upsilon\) | upsilon meson |
| \(\Phi\) | magnetic flux |
| \(\phi\) | phase angle |
| \(\Omega\) | ohm (unit) |
| \(\omega\) | angular velocity |
| \(\text { A }\) | ampere (current unit) |
| \(A\) | area |
| \(A\) | cross-sectional area |
| \(A\) | total number of nucleons |
| \(a\) | acceleration |
| \(a_{\mathrm{B}}\) | Bohr radius |
| \(a_{\mathrm{c}}\) | centripetal acceleration |
| \(a_{\mathrm{t}}\) | tangential acceleration |
| \(\mathrm{AC}\) | alternating current |
| \(\text { AM }\) | amplitude modulation |
| \(\text { atm }\) | atmosphere |
| \(B\) | baryon number |
| \(B\) | blue quark color |
| \(\overline{B}\) | antiblue (yellow) antiquark color |
| \(b\) | quark flavor bottom or beauty |
| \(B\) | bulk modulus |
| \(B\) | magnetic field strength |
| \(B_{\text {int }}\) | electron’s intrinsic magnetic field |
| \(\mathrm{B}_{\mathrm{orb}}\) | orbital magnetic field |
| \(\text { BE }\) | binding energy of a nucleus—it is the energy required to completely disassemble it into separate protons and neutrons |
| \(\mathrm{BE} / A\) | binding energy per nucleon |
| \(\mathrm{Bq}\) | becquerel—one decay per second |
| \(C\) | capacitance (amount of charge stored per volt) |
| \(C\) | coulomb (a fundamental SI unit of charge) |
| \(C_{\mathrm{p}}\) | total capacitance in parallel |
| \(C_{\mathrm{s}}\) | total capacitance in series |
| \(\mathrm{CG}\) | center of gravity |
| \(\text { CM }\) | center of mass |
| \(c\) | quark flavor charm |
| \(c\) | specific heat |
| \(c\) | speed of light |
| \(\text { Cal }\) | kilocalorie |
| \(\text { cal }\) | calorie |
| \(C O P_{\mathrm{hp}}\) | heat pump’s coefficient of performance |
| \(C O P_{\text {ref }}\) | coefficient of performance for refrigerators and air conditioners |
| \(\cos \theta\) | cosine |
| \(\cot \theta\) | cotangent |
| \(\csc \theta\) | cosecant |
| \(D\) | diffusion constant |
| \(d\) | displacement |
| \(d\) | quark flavor down |
| \(\mathrm{dB}\) | decibel |
| \(d_{\mathrm{i}}\) | distance of an image from the center of a lens |
| \(d_{\mathrm{o}}\) | distance of an object from the center of a lens |
| \(\text { DC }\) | direct current |
| \(E\) | electric field strength |
| \(\varepsilon\) | emf (voltage) or Hall electromotive force |
| \(\text { emf }\) | 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 |
| \(\mathrm{EC}\) | electron capture |
| \(E_{\text {cap }}\) | energy stored in a capacitor |
| \(E f f\) | efficiency—the useful work output divided by the energy input |
| \(E f f_{C}\) | Carnot efficiency |
| \(E_{\text {in }}\) | energy consumed (food digested in humans) |
| \(E_{\text {ind }}\) | energy stored in an inductor |
| \(E_{\text {out }}\) | energy output |
| \(e\) | emissivity of an object |
| \(e^{+}\) | antielectron or positron |
| \(\mathrm{eV}\) | electron volt |
| \(\mathrm{F}\) | farad (unit of capacitance, a coulomb per volt) |
| \(\mathrm{F}\) | focal point of a lens |
| \(\mathbf{F}\) | force |
| \(F\) | magnitude of a force |
| \(F\) | restoring force |
| \(F_{\mathrm{B}}\) | buoyant force |
| \(F_{\mathrm{c}}\) | centripetal force |
| \(F_{\mathrm{i}}\) | force input |
| \(\mathbf{F}_{\text {net }}\) | net force |
| \(F_{\circ}\) | force output |
| \(\text { FM }\) | frequency modulation |
| \(f\) | focal length |
| \(f\) | frequency |
| \(f_{0}\) | resonant frequency of a resistance, inductance, and capacitance \((R L C)\) series circuit |
| \(f_{0}\) | threshold frequency for a particular material (photoelectric effect) |
| \(f_{1}\) | fundamental |
| \(f_{2}\) | first overtone |
| \(f_{3}\) | second overtone |
| \(f_{\mathrm{B}}\) | beat frequency |
| \(f_{\mathrm{k}}\) | magnitude of kinetic friction |
| \(f_{\mathrm{s}}\) | magnitude of static friction |
| \(G\) | gravitational constant |
| \(G\) | green quark color |
| \(\overline{G}\) | 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 |
| \(h f\) | photon energy |
| \(h_{\mathrm{i}}\) | height of the image |
| \(h_{\mathrm{o}}\) | 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 |
| \(I_{\text {ave }}\) | average intensity for a continuous sinusoidal electromagnetic wave |
| \(I_{\text {rms }}\) | average current |
| \(\mathrm{J}\) | joule |
| \(J / \Psi\) | Joules/psi meson |
| \(\mathrm{K}\) | kelvin |
| \(k\) | Boltzmann constant |
| \(k\) | force constant of a spring |
| \(K_{\alpha}\) | x rays created when an electron falls into an \(n=1\) shell vacancy from the \(n=3\) shell |
| \(K_{\beta}\) | x rays created when an electron falls into an \(n=2\) shell vacancy from the \(n=3\) shell |
| \(\text { kcal }\) | kilocalorie |
| \(\text { KE }\) | translational kinetic energy |
| \(\mathrm{KE}+\mathrm{PE}\) | mechanical energy |
| \(\mathrm{KE}_{e}\) | kinetic energy of an ejected electron |
| \(\mathrm{KE}_{\mathrm{rel}}\) | relativistic kinetic energy |
| \(\mathrm{KE}_{\mathrm{rot}}\) | rotational kinetic energy |
| \(\overline{\mathrm{KE}}\) | thermal energy |
| \(\mathrm{kg}\) | kilogram (a fundamental SI unit of mass) |
| \(L\) | angular momentum |
| \(\text { L }\) | liter |
| \(L\) | magnitude of angular momentum |
| \(L\) | self-inductance |
| \(\ell\) | angular momentum quantum number |
| \(L_{\alpha}\) | x rays created when an electron falls into an \(n=2\) shell from the \(n=3\) shell |
| \(L_{e}\) | electron total family number |
| \(L_{\mu}\) | muon family total number |
| \(L_{\tau}\) | tau family total number |
| \(L_{\mathrm{f}}\) | heat of fusion |
| \(L_{\mathrm{f}} \text { and } L_{\mathrm{v}}\) | latent heat coefficients |
| \(\mathrm{L}_{\text {orb }}\) | orbital angular momentum |
| \(L_{\mathrm{s}}\) | heat of sublimation |
| \(L_{\mathrm{v}}\) | heat of vaporization |
| \(L_{z}\) | z - component of the angular momentum |
| \(M\) | angular magnification |
| \(M\) | mutual inductance |
| \(\mathrm{m}\) | indicates metastable state |
| \(m\) | magnification |
| \(m\) | mass |
| \(m\) | mass of an object as measured by a person at rest relative to the object |
| \(\mathrm{m}\) | meter (a fundamental SI unit of length) |
| \(m\) | order of interference |
| \(m\) | overall magnification (product of the individual magnifications) |
| \(m\left({ }^{A} \mathrm{X}\right)\) | atomic mass of a nuclide |
| \(\text { MA }\) | mechanical advantage |
| \(m_{\mathrm{e}}\) | magnification of the eyepiece |
| \(m_{\mathrm{e}}\) | mass of the electron |
| \(m_{\ell}\) | angular momentum projection quantum number |
| \(m_{n}\) | mass of a neutron |
| \(m_{\mathrm{o}}\) | magnification of the objective lens |
| \(\mathrm{mol}\) | mole |
| \(m_{p}\) | mass of a proton |
| \(m_{\mathrm{s}}\) | spin projection quantum number |
| \(N\) | magnitude of the normal force |
| \(\mathrm{N}\) | newton |
| \(\mathbf{N}\) | normal force |
| \(N\) | number of neutrons |
| \(n\) | index of refraction |
| \(n\) | number of free charges per unit volume |
| \(N_{\mathrm{A}}\) | Avogadro's number |
| \(N_{\mathrm{r}}\) | Reynolds number |
| \(\mathrm{N} \cdot \mathrm{m}\) | newton-meter (work-energy unit) |
| \(\mathrm{N} \cdot \mathrm{m}\) | newtons times meters (SI unit of torque) |
| \(\text { OE }\) | other energy |
| \(P\) | power |
| \(P\) | power of a lens |
| \(P\) | pressure |
| \(\mathbf{p}\) | momentum |
| \(p\) | momentum magnitude |
| \(p\) | relativistic momentum |
| \(\mathbf{p}_{\text {tot }}\) | total momentum |
| \(\mathbf{p}_{\text {tot }}^{\prime}\) | total momentum some time later |
| \(P_{\text {abs }}\) | absolute pressure |
| \(P_{\text {atm }}\) | atmospheric pressure |
| \(P_{\text {atm }}\) | standard atmospheric pressure |
| \(\text { PE }\) | potential energy |
| \(\mathrm{PE}_{\mathrm{el}}\) | elastic potential energy |
| \(\mathrm{PE}_{\text {elec }}\) | electric potential energy |
| \(\mathrm{PE}_{\mathrm{s}}\) | potential energy of a spring |
| \(P_{\mathrm{g}}\) | gauge pressure |
| \(P_{\text {in }}\) | power consumption or input |
| \(P_{\text {out }}\) | 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 |
| \(\text { QF }\) | quality factor |
| \(R\) | activity, the rate of decay |
| \(R\) | radius of curvature of a spherical mirror |
| \(R\) | red quark color |
| \(\overline{R}\) | antired (cyan) quark color |
| \(R\) | resistance |
| \(\mathrm{R}\) | 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 |
| \(r_{\perp}\) | perpendicular lever arm |
| \(r\) | radius of a nucleus |
| \(r\) | radius of curvature |
| \(r\) | resistivity |
| \(\text { r or rad }\) | radiation dose unit |
| \(\text { rem }\) | roentgen equivalent man |
| \(\mathrm{rad}\) | radian |
| \(\text { RBE }\) | relative biological effectiveness |
| \(R C\) | resistor and capacitor circuit |
| \(\text { rms }\) | root mean square |
| \(r_{n}\) | radius of the nth H-atom orbit |
| \(R_{\mathrm{p}}\) | total resistance of a parallel connection |
| \(R_{\mathrm{s}}\) | total resistance of a series connection |
| \(R_{\mathrm{s}}\) | Schwarzschild radius |
| \(S\) | entropy |
| \(\mathbf{S}\) | 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 |
| \(\sec \theta\) | secant |
| \(\sin \theta\) | sine |
| \(s_{z}\) | z-component of spin angular momentum |
| \(T\) | period—time to complete one oscillation |
| \(T\) | temperature |
| \(T_{\mathrm{c}}\) | 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 |
| \(\tan \theta\) | tangent |
| \(U\) | internal energy |
| \(u\) | quark flavor up |
| \(\mathrm{u}\) | unified atomic mass unit |
| \(\mathbf{u}\) | velocity of an object relative to an observer |
| \(\mathbf{u}^{\prime}\) | velocity relative to another observer |
| \(V\) | electric potential |
| \(V\) | terminal voltage |
| \(\mathrm{V}\) | volt (unit) |
| \(V\) | volume |
| \(\mathbf{v}\) | relative velocity between two observers |
| \(v\) | speed of light in a material |
| \(\mathbf{v}\) | velocity |
| \(\overline{\mathbf{v}}\) | average fluid velocity |
| \(V_{\mathrm{B}}-V_{\mathrm{A}}\) | change in potential |
| \(\mathbf{v}_{\mathrm{d}}\) | drift velocity |
| \(V_{\mathrm{p}}\) | transformer input voltage |
| \(V_{\text {rms }}\) | rms voltage |
| \(V_{\mathrm{s}}\) | transformer output voltage |
| \(\mathbf{v}_{\text {tot }}\) | total velocity |
| \(v_{\mathrm{w}}\) | propagation speed of sound or other wave |
| \(\mathbf{v}_{\mathrm{w}}\) | wave velocity |
| \(W\) | work |
| \(W\) | net work done by a system |
| \(\text { W }\) | watt |
| \(w\) | weight |
| \(w_{\mathrm{fl}}\) | weight of the fluid displaced by an object |
| \(W_{\mathrm{c}}\) | total work done by all conservative forces |
| \(W_{\mathrm{nc}}\) | total work done by all nonconservative forces |
| \(W_{\text {out }}\) | useful work output |
| \(X\) | amplitude |
| \(\mathrm{X}\) | 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 |
| \(X_{\mathrm{C}}\) | capacitive reactance |
| \(X_{\mathrm{L}}\) | inductive reactance |
| \(x_{\text {rms }}\) | 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 |
