Let's convert the wavelength into meters first:
[tex]\lambda=580 nm=580 \cdot 10^{-9}m[/tex]
Then we know that the frequency f is related to the wavelength by the following relationship:
[tex]f= \frac{c}{\lambda} [/tex]
where [tex]c=3\cdot 10^8 m/s[/tex] is the speed of light. Substituting the numbers, we get the frequency:
[tex]f= \frac{3\cdot 10^8 m/s}{580 \cdot 10^{-9}m}=5.2\cdot 10^{14}Hz [/tex]
So, this is approximately the frequency of yellow light.
