SI Units Used For Studying “ElectroMagnetic Radiation”

Physical QuantityPhysical Quantity SymbolMathematical FormulaSI Unit of Physical Quantity
Wavelength\lambda\mathrm{m}
Speed of Lightc_{0}\omega_{0}=299792458 \mathrm{~m} \mathrm{~s}^{-1}m s^{-1}
Wavenumber in Vacuum
\widetilde{\nu}
\widetilde{\nu}=\nu / c_{0}=1 / \lambdam^{-1}
Wavenumber in Medium\sigma\sigma=1 / \lambdam^{-1}
Frequency\nu\nu=c / \lambda\mathrm{Hz}
Angular Frequency\omega\omega=2 \pi \nu\mathrm{s}^{-1}, \mathrm{rad} \mathrm{s}^{-1}
Refractive Indexnn=c_{0} / cNo Unit or Unitless
Planck Constanth\mathrm{J} \mathrm{s}
Radiant EnergyQ, W\mathrm{J}
Radiant IntensityI_{\mathrm{e}}I_{\mathrm{e}}=\mathrm{d} P / \mathrm{d} \Omega\mathrm{W} \mathrm{sr}^{-1}
Radiant ExcitanceMM=\mathrm{d} P / \mathrm{d} A_{\text {soure }}\mathrm{W} \mathrm{m}^{-2}
RadianceLI_{\mathrm{e}}=\int L \cos \Theta \mathrm{d} A_{\text {source }}\mathrm{W} \mathrm{sr}^{-1} \mathrm{~m}^{-2}
Intensity or IrradianceI, EI=\mathrm{d} P / \mathrm{d} A\mathrm{W} \mathrm{m}^{-2}
Spectral Intensity or Spectral IrradianceI_{\widetilde{\nu}}, E_{\widetilde{\nu}}I_{\widetilde{\nu}}=\mathrm{d} I / \mathrm{d} \widetilde{\nu}\mathrm{W} \mathrm{m}^{-1}
FluenceF,(H)F=\int I \mathrm{~d} t=\int(\mathrm{d} P / \mathrm{d} A) \mathrm{d} t\mathrm{J} \mathrm{m}^{-2}
Einstein Coefficient for Spontaneous EmissionA_{i j}\mathrm{d} N_{j} / \mathrm{d} t=-\sum_{i} A_{i j} N_{j}\mathrm{s}^{-1}
Stefan-Boltzmann Constant\sigmaM_{\mathrm{bb}}=\sigma T^{4}\mathrm{W} \mathrm{m}^{-2} \mathrm{~K}^{-4}
First Radiation Constantc_{1}c_{1}=2 \pi h c_{0}^{2}\mathrm{W} \mathrm{m}^{2}
Second Radiation Constantc_{2}c_{2}=h c_{0} / k_{\mathrm{B}}\mathrm{K} \mathrm{m}
Molar RefractivityRR=\left(\frac{n^{2}-1}{n^{2}+2}\right) V_{\mathrm{m}}\mathrm{m}^{3} \mathrm{~mol}^{-1}
Angle of Optical Rotation\alpharadian
Specific Optical Rotatory Power[\alpha]_{\lambda}^{\theta}[\alpha]_{\lambda}^{\theta}=\alpha / \gamma l\mathrm{rad} \mathrm{m}^{2} \mathrm{~kg}^{-1}
Molar Optical Rotatory Power\alpha_{m}\alpha_{\mathrm{m}}=\alpha / c l\mathrm{rad} \mathrm{m}^{2} \mathrm{~mol}^{-1}

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