(a)[3]
Explain why these dark lines occur.
(b(i))[4]
A dark line is seen at a wavelength of $435\,\text{nm}$. Calculate the energy, in eV, of a photon of light of wavelength $435\,\text{nm}$.
(b(ii))[1]
On Fig. 8.2, draw an arrow to show the energy change responsible for this dark line.
(i)[4]
Calculate the energy, in $\text{eV}$, of a photon of light of wavelength $435\,\text{nm}$.
(ii)[1]
On Fig. 8.2, draw an arrow to show the energy change responsible for this dark line.