(a)[3]
Explain how the hydrogen line spectrum serves as evidence for discrete electron energy levels in atoms.
(b(i))[1]
Some electron energy levels in atomic hydrogen are shown in Fig. 7.1. On Fig. 7.1, add an arrow to indicate a third possible transition.
(b(ii))[3]
Calculate the wavelength of the emitted light for the transition in (i).
(c)[4]
A beam of light has a continuous spread of wavelengths from $400\,\text{nm}$ to $700\,\text{nm}$. It is directed onto some cool hydrogen gas, as shown in Fig. 7.2. Using the wavelength values from (b), state and explain what the emergent light spectrum looks like.