Chapter 1
Physical constants
Memorizing these constants is not doing physics. They are provided for
your convenience, but we will give you values for constants on quizzes and
finals. You should memorize the SI unit conventions, and should know the
“approximate values”.
Fundamental constants
Quantity Symbol Value
Speed of light c3.00 ×108m/s
Gravitational constant G6.67 ×10−11 Nm2/kg2
Planck’s constant h6.63 ×10−34 J s
4.14 ×10−15 eV s
Coloumb’s constant k9×109N m2/C2
Permeability of the vacuum µ04π×10−7N s2/C2
Avagadro’s number NA6.023 ×1023 atoms/mole
Boltzmann’s constant kB1.38 ×10−23 J/K
Stephan-Boltzmann constant σ5.67 ×10−8W m−2K−4
Proton charge e1.602×10−19 C
Matter
Particle Mass Charge
Electron 9.11 ×10−31 kg −1.60 ×10−19 C
Proton 1.67 ×10−27 kg 1.60 ×10−19 C
Neutron 1.67 ×10−27 kg 0 C
Approximate values
These figures give you a rough idea of how big various quan-
tites are, such as the well-depth of the Lennard-Jones poten-
tial. Exact values depend on the system being considered.
Quantity Approx. Value
Size of atom ∼10−10 m 1 ˚
A
Well-depth 10−21 J 10−3eV
Ionization energy 10−20 – 10−18 J 0.1 – 10 eV
Mass of an atom 10−27 – 10−25 kg 1 – 200 amu
Visible light :
frequency 6×1014 Hz —
E3×10−19 J 2 eV
Optics
Different colours have slightly different refractive indices.
This table has approximate values for the visible spectrum
(exact values will depend on the exact material and fre-
quency)
Material n=c/vmedium
Vacuum 1.0 (exact)
Air 1.0003
Water 1.33
Glass (crown) 1.50–1.62
Glass (flint) 1.57 – 1.75
Silicon 3.5
Germanium 4.0
Diamond 2.42
Eye 1.33
Eye lens 1.41
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