Final answer:
The transition from n=2 to n=1 in helium emits a photon in the ultraviolet region of the electromagnetic spectrum according to the Rydberg formula.
Step-by-step explanation:
The predicted wavelength of the transition from n=2 to n=1 in helium is in the ultraviolet region of the electromagnetic spectrum. This is due to the Rydberg formula, which can be used to predict the wavelengths of spectral lines of hydrogen-like atoms, which helium can be approximated as when only one electron is present, or when we consider the additional screening effects and reduced mass.
According to the Rydberg formula, transitions to the first energy level (n=1) such as Lyman series transitions for hydrogen, or similar transitions in hydrogen-like atoms, result in ultraviolet radiation. Since the energy difference between these levels increases with the atomic number, the transition in helium should also release a photon in the ultraviolet region.