The frequency associated with photon of radiation having a wavelength of $6000\text{A}°$ is

Wave length, $\lambda =6000\text{Å}\left(\text{or}\right)\lambda =6000\times {10}^{-10}\text{m}$

$\lambda =6\times {10}^{-7}\text{m}$; $\text{\hspace{0.17em}Since,\hspace{0.17em}\hspace{0.17em}}1\text{Å}={10}^{-10}\text{m}$

$\nu =\frac{\text{C}}{\lambda }$ ;  $(\text{C}=3\times {10}^8\text{m/s})$

$\therefore \text{Frequency,}\nu =\frac{3\times {10}^8}{6\times {10}^{-7}}=5\times {10}^{14}{\sec }^{-1}\left(\text{or}\right)\text{Hz}$