LaTeX Forum

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\begin{align*} 
E_{ph, g} &= W_{A} \\
\dfrac{h*c}{\lambda_{g}}&=W_{A} \\
\lambda_{g}&=\dfrac{h*c}{W_{A}}=\dfrac{6,62*10^{-15}*2,99*10^{8}}{1,70} m \approx 7,29*10^{-9} m \approx 729 nm \\
\end{align*} 

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\begin{document}
  \begin{align*}
    E_{ph,g} &= W_A \\
    \frac{h\cdot c}{\lambda_g} &= W_A \\
    \lambda_g &=\frac{h\cdot c}{W_A}=\frac{\num{6,62E-15}\cdot\num{2,99E8}}{\num{1,70}}\,\si{\metre} \\
		&\approx \SI{7,29E-9}{\metre} \\
		&\approx\SI{729}{\nm}
\end{align*}
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