PHYSICAL CONSTANTS* 



1 Angstrom unit 

 1 micron 

 1 millimicron 

 Velocity of light c 

 1 electron volt (ev) 



1 Mev 



i 2 eV L 



2 300 



For photons X = 



For electrons X = 



Electron charge e = 



Mass of electron thq = 



Boltzmann's constant k = 



Planck's constant h = 



Mass of H 1 atom 



Mass of alpha particle 



Mass of proton 



Compton shift at 90° h/mc 



log, 10 



logio 2.718 



Exponential e 



Common log 



Natural log 



->-8 



cm 



1 A = 10- 



10~ 3 mm 



10~ 6 mm 



2.99776 X 10 10 cm sec -1 



1.6020 X 10- 12 erg 



10 6 ev 



he . 



— (V m volts, e in esu) 

 X 



12,395 o m . 

 — A (V in volts) 



150 o 



— A (V in volts) 



4.8025 X 10" 10 esu 



4.8025 X 10- 10 /c = 1.6020 X lO -20 



9.1066 X 10~ 28 gram 



^o _ 8.31436 X 10 7 erg • deg" 1 • mole 



iV^ " 6.0228 X 10 23 mole" 



1.38047 X 10~ 16 erg • deg- 1 



6.624 X 10~ 27 erg sec 



1.6734 X 10" 24 gram 



6.6442 X 10~ 24 gram 



1.67248 X 10- 24 gram 



0.024265 A 



2.3026 



0.4343 



2.71828 



natural log X 0.4343 



common log X 2.3026 



emu 



.-i 



* As of August 1941. By R. T. Birge, Rev. Mod. Phys., 13, 233, 1941. 



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