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Physical Constants

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Constant	Symbol	Metric Units	U.S. Customary Units
Avogadro's number	N0	6.022136x1023 mol-1	x
Boltzmann Constant	k	1.380658x10-23 J/K	x
Planck's Constant	h	6.626076x10-34 Js	x
Universal Gas Constant	or or Ru	8.3145 kJ kmol K	1545 ft lbf lb mol R or 1.9859 Btu lb mol R
Atomic Mass Unit	m0	1.660540x10-27 kg	x
Velocity of Light	c	2.997925x108 m/s	x
Electron Charge	e	1.602177x10-19 C	x
Electron Mass	me	9.1093897x10-31 kg	x
Proton Mass	mp	1.6726231x10-27 kg	x
Neutron Mass	mn	1.6749286x10-27 kg	x
Gravitation Constant (Std.)	g	9.80665 m/s2	32.174 ft/s2
Stefan Boltzmann Constant	σ	5.67051x10-8 W/m2 K4	x