The wavelength is given by:
[tex]\lambda=\frac{v}{f}[/tex]where v is the velocity and f is the frequency. In this case the velocity is that of light since this is an electromagnetic radiation and the frequency is given, then we have:
[tex]\begin{gathered} \lambda=\frac{3\times10^8\text{ m/s}}{3.24\times10^{13}\text{ Hz}} \\ \lambda=9.26\times10^{-6}\text{ m} \end{gathered}[/tex]Therefore, the wavelength is:
[tex]\lambda=9.26\times10^{-6}\text{m}[/tex]