Question

The portion of the visible spectrum that appears brightest to the human eye is around 562 nm in wavelength, which corresponds to yellow-green. the speed of light is 3 × 108 m/s. what is the frequency of 562 nm light? answers

Answer 1

The relationship between frequency and wavelength for electromagnetic waves is 
$f= \frac{c}{\lambda}$
where
f is the frequency
c is the speed of light
$\lambda$ is the wavelength

The light in our problem has a wavelength of 
$\lambda=562 nm=5.62 \cdot 10^{-7} m$
so its frequency is (using the previous equation)
$f= \frac{c}{\lambda}= \frac{3 \cdot 10^8 m/s}{5.62 \cdot 10^{-7}m} =5.34 \cdot 10^{14} Hz$