# PHYSICAL CONSTANTS

```MECHANICS AND CLASSICAL PHYSICS

Gravitational constant             6.67 x 10-11 N m2 kg-1
Acceleration due to gravity, g     9.80 m/s2 = 32 ft/s2
Speed of sound in dry air (stp)    331 m/s

ASTRONOMICAL

Length of earth year               3.16 x 107 sec
Radius of the earth                6.38 x 106m = 3965 miles
Mean radius of the earth's orbit   1.49 x 1011 m = 9.26 x 107 miles
Mass of the earth                  5.98 x 1024 kg
Weight of the earth                3.3 x 1018 lb

HEAT AND KINETIC THEORY

Avogadro constant NA               6.02 x 1026 kmole-1
Boltzmann constant                 1.38 x 10-23 J K-1
Universal gas constant             8310 J kmole-1 K
Absolute zero, 0°K                 -273 C = 460 F
Volume of 1 kmole (stp)            22.4 m3 kmole
Mechanical equivalent of heat      4185 J kcal-1

LIGHT

Vacuum speed of light              2.9979 x 108 m/s
Ångstrom unit                      10-10 m

ELECTRICAL

Coulomb law constant               9.00 x 109 N m2 C2
Permittivity of free space, eo     8.85 x 10-12 F m-1
Permeability of free space, mo     4 p x 10-7 H m-1
Faraday                            9.65 x 104 C m-1

ATOMIC AND NUCLEAR PHYSICS

Rest mass of the electron          9.1091 x 10-31 kg  = 0.511 MeV
Electron charge                    1.6021 x 10-19 C
Specific charge of electron, e/m   1.7588 x 1011 C/kg
Planck's constant                  6.6257 x 10-34 J sec = 4.136 x 10-15eV s
Unified atomic mass unit (u)       1.661 x 10-27 kg  = 931 MeV
(1/12 mass carbon 12 = 1/NA)
1 curie = 3.700 x 1010 disintegrations/s
1 Angstrom unit = 10-10 meter = 105 Fermi
1 Fermi = 10-15 meter

SPECIFIC HEAT CAPACITIES

kc kg-1C-1   J kg-1K-1
ice       0.5         2000
water     1.0         4190
steam     0.48        2010
iron      0.11         470
aluminum  0.22         910
mercury   0.033        138
glass     0.16         837

LATENT HEATS OF TRANSFORMATION

kC kg-1      J kg-1
steam-water     540           334 x 103
ice-water       80           2256 x 103

LINEAR EXPANSION COEFFICIENT

aluminum   22.2 x 10-6 C-1
brass      18.8
copper     16.2
steel      13.4
iron       11.7

ELASTIC MODULI

In units: 1010 N/m2 = 109 dyne/cm2

METAL     YOUNG SHEAR  BULK
Aluminum  7.0   3.0    7.0
Brass     9.1   3.6    6.1
Copper   11.0   4.22  14.0
Iron     19.0   7.0   10.0
Steel    20.0   8.4   16.0
Tungsten 36.0  15.0   20.0

STATIC FRICTION COEFFICIENT

glass on glass		0.9 to 1.0
wood on wood		0.25 to 0.5
wood on metals		0.2 to 0.6
leather on metal	0.6
rolling friction	0.004-0.006
steel on steel, 20°C, lubricated with light machine oil: 0.16

INDEX OF REFRACTION

Na (D)  Hg(grn)
5890 Â  5461 Â

water            1.3330  1.3345
glass, crown     1.5170  1.5191
glass, flint     1.6499  1.6546
alcohol, ethyl   1.367
lucite	         1.47

DENSITY

DENSITY OF SOLIDS

aluminum          2.7 gm/cm3
brass             8.4
copper            8.9
crown glass       2.5 to 2.7
flint glass       3.0 to 3.6
gold              19.3
iron and steel    7.88
nickel            8.8
silver            10.5
wood, oak         0.60 to 0.90
wood, pine        0.35 to 0.50
zinc              7.1

DENSITY OF LIQUIDS

alcohol, ethyl	        0.79
alcohol, methyl         0.81
gasoline                0.68 to 0.75
glycerine               1.26
mercury                13.6
turpentine              0.87
water                   1.00

DENSITY OF GASES

air                     0.001293
carbon dioxide          0.001975
helium                  0.000179
hydrogen                0.000089
nitrogen                0.000125
oxygen                  0.00143

RESISTIVITY OF METALS

aluminum             2.63 x 10-8 W m
brass                6.4 to 8.4
constantin          49
copper (annealed)    1.72
copper (hard drawn)  1.60
iron (annealed)      9.70
iron (hard drawn)   15.0
silver               1.63
German silver       33.0
mercury              6.93
manganin            44

SPECTRAL LINE WAVELENGTHS

Wave lengths of prominent spectral lines, in Ångstroms:

Mercury discharge

6232 orange
6152 orange
5791 yellow
5770 yellow
5461 green (bright, yellowish)
4960 green (faint)
4916 blue-green (faint)
4358 blue
4078 violet
4047 violet

Sodium flame or discharge

5890 yellow (D2 line)
5896 yellow

Neon discharge

6929   6599   6507   6402   6383   6334   6217   6164
6143   6074   6030   5882   5852   5401   5341

Hydrogen discharge

6563 red
4861 blue-green
4340 blue
4102 blue
3970 violet
3889 violet

Helium discharge

7281
7065 red
6678 red
5876 yellow
5048 blue-green (faint)
5016 blue-green
4922 blue-green (faint)
4713 blue
4686 blue
4471 blue
4438 blue (faint)
4388 blue (faint)
4144
4121
4026
3965
3889 violet

Argon discharge

4628   4596   4511   4345   4334   4300   4272   4266
4259   4201   4198   4191   4182   4164   4159

NUCLIDE MASS, in atomic mass units (u):

Z   A   Name      Symbol   Nuclide      Half
Mass (u)     life

electron   e       .00055
0   1    neutron    n      1.008665     10.8 min
1   1    Hydrogen   H      1.007825
1   2    Deuterium  D      2.014102
1   3    Tritium    T      3.016050     12.26 yr
2   3    Helium     He3    3.016030
2   4    Helium     He4    4.002603
2   5    Helium     He5    5.0123
2   6    Helium     He6    6.018892      0.802 s
3   5    Lithium    Li5    5.01250
3   6    Lithium    Li6    6.01702
4   9    Beryllium  Be9    9.01218
26  56   Iron       Fe56  55.9349
26  57   Iron       Fe57  56.9354

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© 1999, 2004, by Donald E. Simanek.