Question

express the wavelength 400nm in frequency​

Answer 1

Answer:

We know that v=λf where v is velocity, λ is wavelength and f is frequency.

Here v=c=3*10⁸ m/s

400 nm=4×10⁻⁷ m

v=λf

∴3*10⁸=4*10⁻⁷*f

∴f=3*10⁸/4*10⁻⁷

∴f=0.75*10¹⁵

So f=7.5*10¹⁴ Hz