Which provides evidence for the existence of energy levels in nuclei? A the Rutherford alpha particle scattering experiment B the existence of X-ray line spectra C the existence of gamma radiation D electron diffraction by crystals - AQA - A-Level Physics - Question 29 - 2022 - Paper 2

The existence of X-ray line spectra is crucial evidence of energy levels. When electrons transition between energy levels in an atom, they emit X-rays at specific frequencies, which supports the idea of quantized energy levels.

The existence of gamma radiation can be associated with nuclear transitions between energy levels. Gamma rays are emitted when a nucleus transitions from a higher energy state to a lower one, thus providing direct evidence of energy levels within the nucleus.

Electron diffraction by crystals is primarily related to the wave nature of electrons and the arrangement of atoms in a crystal structure, not directly to energy levels in the nucleus.