One requires $11 \text{eV}$ of energy to dissociate a carbon monoxide molecules into carbon and oxygen atoms. The minimum frequency of the appropriate electromagnetic radiation to achieve the dissociation lies in:

Here it is given, the energy required to dissociate a carbon monoxide molecule into carbon and oxygen atoms is  $E=11eV$. We know that $\mathrm{E}=\mathrm{h\vartheta }$ where $\mathrm{h}=6.62\times {10}^{-34}\mathrm{Js}$  and $\vartheta$ is frequency 
 $$\begin{gathered} \Rightarrow 11eV=h\vartheta \\ \Rightarrow \vartheta =\frac{11\times 1.6\times {10}^{-19}}{6.62\times {10}^{-34}}=2.65\times {10}^{15}\mathrm{Hz} \end{gathered}$$
This frequency radiation belongs to ultraviolet region.
When energy of the given photon is in electron volt  then   wavelength will  be $\mathrm{given} \mathrm{by} \mathrm{\lambda }=\frac{12432}{11}\mathrm{\AA }=1130.18\times {10}^{-10} \mathrm{m}$    

this wavelength of the photon is in ultraviolet region 

 $$\begin{gathered} \left[E=\frac{hc}{\lambda } \\ \Rightarrow \lambda \left(in \mathrm{\AA }\right)=\frac{hc}{E} =\frac{12432}{E} \right] \end{gathered}$$