# Physical Constants in CGS Units speed of light c

```Physical Constants in CGS Units speed of light c=3× 1010cm/sec = 1000 ft/µsec = 1 ft/nanosecond
acceleration due to gravity at the surface of the earth g = 980 cm/sec2 = 32 ft/sec2 gravitational
constant G = 6.67× 10– 8cm3/(gm sec2) charge on an electron e = 4.8× 10– 10esu Planck's constant h =
6.62× 10– 27erg sec (gm cm2 /sec ) Planck constant /2π h = 1.06× 10– 27erg sec (gm cm2 / sec ) Bohr
radius a0 = .529× 10– 8 cm rest mass of electron me = 0.911×10– 27gm rest mass of proton Mp = 1.67×
10 – 24gm rest energy of electron mec2 = 0.51 MeV ( ≈ 1 / 2 MeV) rest energy of proton Mpc2 = 0.938
BeV ( ≈ 1 BeV) proton radius rp = 1.0×10– 13cm Boltzmann's constant k = 1.38× 10 – 16ergs/ kelvin
Avogadro's number N0 = 6.02× 10 23molecules/mole absolute zero = 0°K = 273°C density of mercury =
13.6 gm / cm3 mass of earth = 5.98× 10 27gm mass of the moon = 7.35× 10 25gm mass of the sun =
1.97× 10 33gm earth radius = 6.38× 10 8 cm = 3960 mi moon radius = 1.74× 10 8 cm = 1080 mi mean
distance to moon = 3.84× 10 10cm mean distance to sun = 1.50× 10 13cm mean earth velocity in orbit
about sun = 29.77 km / sec Conversion Factors 1 meter = 100 cm (100 cm/meter) 1 in. = 2.54 cm (2.54
cm/in.) 1 mi = 5280 ft (5280 ft/mi) 1 km (kilometer) = 105 cm (105 cm / km) 1 mi = 1.61 km = 1.61× 105
cm (1.61× 105 cm/mi) 1 A ° (angstrom ) = 10 – 8 cm (10 – 8 cm / A ° ) 1 day = 86,000 sec (8.6× 104 sec /
day ) 1 year = 3.16× 107 sec (3.16× 107 sec/year) 1 µ sec (microsecond ) = 10 – 6 sec (10 – 6 sec / µ sec )
1 nanosecond = 10 – 9 sec (10 – 9 sec /nanosecond ) 1 mi/hr = 44.7 cm/sec 60 mi/hr = 88 ft/sec 1 kg
(kilogram) =10 3 gm (10 3 gm / kg) 1 coulomb = 3× 109 esu (3× 109 esu/coulomb) 1 ampere = 3× 109
statamps (3× 109 statamps/ampere) 1 statvolt = 300 volts (300 volts/statvolt) 1 joule = 107 ergs (107
ergs / joule ) 1 W (watt) = 107 ergs/ sec (107 erg / W) 1 eV = 1.6× 10– 12ergs (1.6× 10– 12ergs/eV) 1
MeV = 106 eV (106 eV /MeV) 1 BeV = 109 eV (109 eV /BeV) 1 µ (micron ) pressure = 1.33 dynes / cm2 1
cm Hg pressure = 104 µ 1 atm = 76 cm Hg = 1.01×106 dynes/cm2
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