Light that is blue has a wavelength of 4.75 x meters. What is blue light's frequency?

Apply this equation to find the blue light's frequency:

c = fλ

c = speed of light in a vacuum, f = frequency, λ = wavelength

Given values:

c = 3*10⁸m/s, λ = 4.75*10⁻⁹m

Plug in and solve for f:

3*10⁸ = f (4.75*10⁻⁹)

f = 63.2 petahertz