Answer
Frequency: $4.55\times 10^{14}\text{ Hz}$ (red light)
Work Step by Step
We calculate the frequency $f$ using the formula:
$f=\frac{c}{\lambda}$
where
$c=3.00\times 10^8\text{ m/s}$
$\lambda=660\text{ nm}=6.60\times 10^{-7}\text{ m}$
$f=\frac{3.00\times 10^8}{6.60\times 10^{-7}}=4.55\times 10^{14}\text{ Hz}$
This corresponds to red light, which is commonly used in photosynthesis to drive energy conversion in chlorophyll.
