Physical Constants and Conversions

Basic

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  Speed of light in vacuum c = 2.997 924 580 e8 m/s (exact)
  
  
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  Planck's constant
  
  
  
  • 
    h = 6.6260755e-34 J-s
    
  • 
    h = 4.136e-15 eV-s
    
  • 
    hbar = h/2\pi = 1.05457266e-34 J-s
    
  • 
    hbar = 6.57e-16 eV-s
    
  
  
  
• 
  electron charge q = 1.60217733e19 coulomb
  
  
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  Gravitational Constant G 6.7259e-11 N m**2/kg**2
  
  
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  Boltzmann's constant
  
  
  
  • 
    k = 1.380658e-23 J/K
    
  • 
    k = 8.617e-5 eV/K
    
  
  
  
• 
  Stephan-Boltzmann constant \sigma = 5.67051e-8 W/m**2/K**4
  

Electrical

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  Permittivity of free space
  
  
  
  • 
    \epsilon = 8.854e-12 F/m = 1/c**2\mu
    
  • 
    \epsilon = 55.3 e/V-micron
    
  
  
  
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  Permeability of free space \mu = 4 \pi e-7 H/m or Tesla/ampere
  
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  Coulomb constant 8.988e9 N-m**2/coul**2
  
  
• 
  Wavelength of a 1eV photon 1.243e-6 m
  
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  thermal electron voltage (r.t.) kT/q = 25.86 mv
  
• 
  energy of electron (r.t.) kT = .02586 eV
  
• 
  energy (1 electron volt) 1 ev = 1.602e-19 J
  
• 
  Quantum Hall Resistance 25812.8056 ohms
  

Nuclear

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  Electron Rest Mass 9.1093897e-28 g
  
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  Proton Rest Mass 1.6726231e-24 g
  
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  Neutron Rest Mass 1.6749286e-24 g
  
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  Magnetic flux quantum (hc/2e) 2.06783461e-15 Wb
  
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  Quantum of circulation (h/2m_e) 3.63694807e-4 m**2/s
  
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  Specific Electron Charge -e/m_e - 1.75881962e11 Coul/kg
  
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  Electron Magnetic Moment \mu_e 9.2847701e-24 J/T
  
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  Bohr Magneton 9.2740154e-24 J/Tesla
  
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  Nuclear Magneton e h-bar/2m_p 5.0507866e-27 J/T
  
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  Proton Magnetic Moment \mu_p 1.41060761e-26 J/T
  

Chemistry/Thermo

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  Faraday Constant F 9.6485309e4 Coulombs/mole
  
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  Gas Constant R 8.314510 J/K/mole
  
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  energy (calories) 1 cal = 4.184 J
  
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  Bohr radius .529 angstrom
  
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  Avogadro's number 6.0221367e23 atoms/mole
  
  
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  Molar volume
  
  
  
  • at 273.15K 1e5 Pa 22.71108e-3 m**3/mole
    
  • at 273.15K 1 atm 22.41410e-3 m**3/mole
    
  
  
  
• 
  atomic mass unit 1.6605402e-24 g
  

Pressures

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  Standard pressure (1 atm) 1.01325e5 Pa (Newton/m**2)
  
• 
  1 Torr = 1 mm Hg = 133.3 N/m**2 = 133.3 Pa
  
• 
  1 psi = 6.89e3 Pa
  

Radioactivity

• 
  1 Curie 3.7e10 counts/s
  

Astronomical Units

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  Solar Mass 1.989e33 g
  
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  Solar Radius 6.9599e10 cm
  
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  Solar luminosity 3.826e33 ergs/s
  
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  Gravity at solar surface 2.74e4 cm/s**2
  
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  Earth mass 5.976e27 g
  
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  Earth equatorial radius 6378.164 km
  
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  Gravity at earth's surface 980.665 cm/s**2
  
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  Astronomical Unit 1.4959780e13 cm
  
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  Solar effective temperature 5800K
  
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  Solar magnitude -26.73
  
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  Solar constant (1976) .1353 W/cm**2
  
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  Julian century 36525 ephemeris days
  
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  Tropical year (1900.0) 365.242 days
  
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  Tropical year (1900.0) 3.1557e7 ephemeris seconds
  
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  Ephemeris Day 86400 ephemeris seconds
  
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  solar motion velocity 19.7 km/s
  
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  Julian date for 1 Jan 1981: 2444605.5 days
  
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  parsec 3.261633 light years
  
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  parsec 3.085678e18 cm
  
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  light year 9.460530e17 cm
  
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  Xu 1.00208e-11 cm
  
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  flux unit = Jansky = 1e-26 W/m**2/Hz
  
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  Hubble constant 100 km/s/Mpc
  

Optical Constants

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  1 candle = 1 lumen/steradian
  
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  1 candle/m**2 = 3.142e-4 lambert
  
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  1 lambert = 2.054 candles/in**2
  
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  1 lux = 1 meter-candle
  
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  1 lux = .0929 foot-candle
  
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  1 lumen = 1 candle into an angle of 1 steradian
  
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  1 lumen = .001495 watts of light at 546 nm