Question

Calculate the frequency in hertz of electromagnetic radiation that has a wavelength of 720.0 nm. (c = 3.00 X 10⁸ m/s)

Answer 1

We use the relation between the speed of light $c$ , the frequency $\nu$, and wavelength $\lambda$ and we proceed as follows:

$c=\lambda\nu \implies \nu=\cfrac{c}{\lambda} \\ \nu=\cfrac{3\times10^{8}\frac{m}{s}}{720\times10^{-9}\,m}=4.166\times10^{14}\,{s}^{-1}$

Since 1/s or s^-1 is equal to 1 Hz, we have the frequency as $\nu=4.166\times10^{14}\text{ Hz}$

Reference

• Chang, R., & Goldsby, K. A. (2010). Chemistry. Chemistry, 10th ed.; McGraw-Hill Education: New York, NY, USA.