What information does an empirical formula give ?

Im sure its D

Empirical formula has the lowest number (simplified) version in an equation of molecules

d. 671.6 nm

Explanation:

It is possible to solve the wavelength of a radiation from its frequency -or vice versa- using:

λ = c / f

Where λ is wavelength,

c is speed of light, a constant (2.998x10⁸m/s)

And f is frequency: 4.464x10¹⁴s⁻¹

Replacing:

λ = 2.998x10⁸m/s / 4.464x10¹⁴s⁻¹

λ = 6.716x10⁻⁷m

As 1m = 1x10⁹nm:

6.716x10⁻⁷m * (1x10⁹nm / 1m) = 671.6nm

Right answer is: