The energy of an electromagnetic radiation is $19.875 imes 10^{-13}$ ergs. What is its wave number in $\mathrm{cm}^{-1}$ ? $\left(h=6.625 imes 10^{-27}ight.$ erg sec, $\left.c=3 imes 10^{10} \mathrm{~cm} \mathrm{sec}^{-1}ight)$

Question

The energy of an electromagnetic radiation is $19.875 	imes 10^{-13}$ ergs. What is its wave number in $\mathrm{cm}^{-1}$ ? $\left(h=6.625 	imes 10^{-27}ight.$ erg sec, $\left.c=3 	imes 10^{10} \mathrm{~cm} \mathrm{sec}^{-1}ight)$

Aicharya · Accepted Answer

$\begin{aligned} & E=h v=h 	imes \frac{c}{\lambda}=h 	imes c \cdot \bar{v} \ & 	herefore \quad \bar{v}=\frac{E}{h c}=\frac{19.875 	imes 10^{-13}}{6.625 	imes 10^{-27} 	imes 3 	imes 10^{10}}=10^4\end{aligned}$

The energy of an electromagnetic radiation is $19.875 \times 10^{-13}$ ergs. What is its wave number in…

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