Final answer:
The transition in the Balmer series for the given 434 nm emission from a hydrogen lamp is the n = 5 to n = 2 transition.
Step-by-step explanation:
The transition in the Balmer series that corresponds to a photon emitted from a hydrogen lamp with a wavelength of 434 nm is given by the transition where the electron falls from a higher energy level to the second energy level (n = 2). According to the provided information, the n = 5 to n = 2 transition results in the emission of a photon with a wavelength of 434 nm. This is the transition that matches the one observed in the hydrogen lamp. The Balmer series is a categorization of the hydrogen emission spectrum for transitions that terminate in the second energy level (n = 2). Visible wavelengths are produced when electrons transition from higher energy levels (n ≥ 3) to the n = 2 level. As such, in this case, the transition from n = 5 to n = 2 corresponds to a blue light emission with a wavelength of 434 nm, matching the description provided by the question.