Last changed on October 16, 1995
speed of light in a vacuum c 2.99792458(1.2) x 10**8 m/s
elementary charge e 1.60217733(49) x 10**-19 C
Plank's constant h 6.6260755(40) x 10**-34 J s
Avogadro constant N(A) 6.0221367(36) x 10**23 atoms/mole
Unified mass unit u 1.66 05402(10) x 10**-27 kg
electron rest mass m(e) 9.1093897(54) x 10**-31 kg
5.48579903(13) x 10-**-4 u
Proton rest mass m(p) 1.6726231(10) x 10**-27 kg
1.007276470(12) u
Neutron rest mass m(n) 1.6749286(10) x 10**-27 kg
1.008664904(14) u
Bohr radius a(o) 0.529177249(24) x 10**-10m
Classical electron radius r(e) 2.81794092(38) x 10**-15 m
Bohr magneton u(B) 9.2740154(31) x 10**-24 J/T
Nuclear magneton u(N) 5.0507866(17) x 10**-27 J/T
Electron magnetic moment u(e) 9.2847701(31) x 10**-24 J/T
Proton magnetic moment u(p) 1.41060761(47) x 10**-26 J/T
Proton gyromagnetic ratio p 2.6752212(81) x 10**8 /(sec T)
Radioactivity Ci 3.7 x 10**10 Bq