What features of hydrogen spectra could the original Bohr model not explain?

While the Bohr model successfully explained the primary spectral lines of hydrogen by introducing quantized energy levels, it had significant limitations regarding the fine details of these spectra.12

Specifically, the original model could not explain the following features:

• Fine Structure: High-resolution spectroscopy revealed that individual spectral lines of hydrogen are actually composed of several closely spaced fine lines, which the original model did not account for.1
• Magnetic Field Effects: The model could not explain the splitting of spectral lines that occurs when atoms are placed in a magnetic field, such as the frequency shifts associated with the Zeeman effect.1
• Transition Probabilities: The theory was incapable of predicting the likelihood or intensity of transitions between different energy levels.3

These discrepancies necessitated the development of more advanced theories, such as quantum mechanics and quantum electrodynamics, to fully describe the behavior of electrons and the resulting spectral phenomena.13