Physical Constants
This page contains some basic Physical Constants, as well as some common materials properties.
While efforts have been made to ensure the accuracy of the information the reader is cautioned to verify the information, prior to use. (Updated Feb 2009)
GENERAL CONSTANTS
|
Avogadro's number |
Na | 6.02214 x 10^23 molecules/mole | |
| astronomical unit | A.U. | 1.49597870 x 10^11 m | 4.90806660 x 10^11 ft |
| electron charge (elementary charge) | e | 1.60210 x 10^-19 coulombs | |
| electron rest mass | me | 9.10938 x 10^-31 kg | |
| Proton rest mass | mp | 1.67262 x 10^-27 kg | |
| Neutron rest mass | mn | 1.67493 x 10^-27 kg | 1.068846 x 10^-9 ft^3/lb/s^2 |
| Charge to mass ratio for electron | e/me | 1.75874 x 10^11 C kg^-1 | |
| Electron radius | re | 2.81794 x 10^-15 m | |
| Quantum-charge ratio | h/e | 4.13586 x 10^-15 J s C^-1 | |
| Compton wavelength of electron | lambda | 2.42631 x 10^-21 m | |
| Compton wavelength of neutron | 1.31959 x 10^-15 m | ||
| Compton wavelength of proton | 1.32141 x 10^-15 m | ||
| Rydberg constant | R(infinity subtext) | 1.0973731 x 10^7 m^-1m | |
| Muon mass | 1.88353 x 10^-28 kg | ||
| Faraday constant | F | 9.64853 x 10^4 C mol^-1 | |
| ideal gas constant | R | 8.31447 Joules per mole degree Kelvin | |
| Molar volume ideal gas | V0 | 2.2414 x 10^-2 m^3 mol^-1 | |
| Boltzmann constant | k | 1.38065 x 10^-23 joules per degrees kelvin | |
| First radiation constant | c1 | 3.74177 x 10^-16 W m^2 | |
| Second Radiation Constant | c2 | 1.43878 x 10^-2 metres by degrees Kelvin | |
| Wien displacement constant | b | 2.8978 x 10^-3 metres by degrees kelvin | |
| Stefan-Boltzmann constant | theta | 5.6704 x 10^-8 W m^-1 ¡K^-4 | |
| Thosmson cross section | 8ß(re^2)/3 | 6.6516 x 10^-29 m^2 | |
| Gyromagnetic ration of proton | 2.67519 x 10^8 rad s^-1 T^-1 | ||
| Bohr Magneton | µB | 9.27401 x 10^-24 J T^-1 | |
| Nuclear Magneton | µN | 5.0508 x 10^-27 J T^-1 | |
| Proton Moment | µp | 1.41061 x 10^-26 J T^-1 | |
| Electron magnetic Moment | µe | 9.28476 x 10^-24 J T^-1 | |
| Neutron magnetic Moment | µn | 9.662364 x 10^-27 J T^-1 | |
| Muon magnetic Moment | µµ | 4.490451 x 10^-26 J T^-1 | |
| Electron-volt | eV | 1.60210 x 10^-19 J(eV)^-1 | |
| Zeeman splitting constant | µB/hc | 4.6685 x 10 m^-1 T^-1 | |
| Planck's constant | h | 6.626069 x 10^-34 Joule seconds | |
| Fine Structure Constant | alpha | 7.29735 x 10^-3 J s | |
| Poisson's Ratio (elastic isotropic materials) |
µ | 0.25 | |
| speed of light in a vacuum | c | 2.997925 x 10^8 m/s | 9.83571056 x 10^8 ft/s |
| standard gravitational acceleration | go | 9.80665 m/s^2 | 32.17404856 ft/s^2 |
| standard atmosphere | atm | 101325 Pa | 14.6959 psi |
| universal gravitational constant | G | 6.670 x 10^-11 m^3/kg/s^2 | 1.068846 x 10^-9 ft^3/lb/s^2 |
| atomic mass unit | µ | 1.66054 x 10^-27 kg | |
| Bohr radius | a0 | 5.29177 x 10^-11 m | |
Energy Associated With
| Unified atomic mass unit | c^2/Ne | 9.31478 x 10^8 eV u^-1 | |
| Proton Mass | mp c^2 / e | 9.38256 x 10^8 eV mp^-1 | |
| Neutron mass | mn c^2 / e | 9.39550 eV mn^-1 | |
| Electron mass | me c^2 /e | 5.11006 x 10^5 eV me^-1 | |
| Cycle | e/h | 2.41804 x 10^14 Hz(eV)^-1 | |
| Wavelength | ch/e | 1.23981 x 10^-6 eV m | |
| Wave number | e/ch | 8.06573 x 10^5 m^-1(eV)^-1 | |
| ¡K | e/k | 1.16049 x 10^4 ¡k(eV)^-1 |
STATIC (µs) AND KINETIC (µk) FRICTION COEFFICIENTS
| µs | µk | ||
|
steel |
0.4 | 0.3 | |
| ice | 0.02 | 0.01 | |
| wood | 0.2 | 0.2 | |
| plastic | 0.2 | 0.2 | |
| clay | 0.9 | 0.8 | |
| rubber | 0.9 | 0.8 | |
| rock | 0.4 | 0.3 |
STRUCTURAL STEEL
|
modulus of elasticity |
Es | 29000 ksi | 200000 MPa |
| coefficient of thermal expansion | c | 6.5x10^-6 per °F | 11.7x10^-6 per °C |
| Poisson's Ratio | µ | 0.28 | |
| Shear modulus of elasticity | Gs | 78000 MPa | |
ALUMINUM
|
modulus of elasticity |
Ea | 10150 ksi | 70000 MPa |
| coefficient of thermal expansion | c | 13x10^-6 per °F | 23.4x10^-6 per °C |
| Poisson's Ratio | µ | 0.33 | |
| Shear modulus of elasticity | Ga | 26000 MPa | |
CONCRETE
|
modulus of elasticity |
Ec | 57000(f'c)^0.5 psi | 5000(f'c)^0.5 MPa |
| coefficient of thermal expansion | c | 5.7x10^-6 per °F | 10.0x10^-6 per °C |
| Poisson's Ratio | µ | 0.15 to 0.2 | |
MASONRY
|
modulus of elasticity |
Em | 1000f'm MPa | |
| coefficient of thermal expansion | c | 3.4x10^-6 per °F | 6.1x10^-6 per °C |
| shear modulus | Ev | 400f'm MPa | |
TIMBER
|
modulus of elasticity (varies with species) |
Et | 1000000 to 1930000 psi | 6000 to 12500 MPa |
| coefficient of thermal expansion | c | 22x10^-6 per °F | 40x10^-6 per °C |
GLASS FIBER
|
modulus of elasticity |
E | 4350 ksi | 30000 MPa |
| tensile strength | t | 87 ksi | 600 MPa |
GLASS & CARBON FIBER
|
modulus of elasticity |
E | 5365 ksi | 37000 MPa |
| tensile strength | t | 87 ksi | 600 MPa |
CARBON FIBER
|
modulus of elasticity |
E | 14500 ksi | 100000 MPa |
| tensile strength | t | 174 ksi | 1200 MPa |
ARAMID FIBER
|
modulus of elasticity |
E | 7830 ksi | 54000 MPa |
| tensile strength | t | 189 ksi | 1300 MPa |