Answer: Ultraviolet region.
- A Visible region
- B Infrared region
- C Ultraviolet region
- D X-ray region
Correct answer: C. Ultraviolet region
Explanation: Lyman series: transitions to n=1. High energy, short wavelength: ultraviolet region.

The Geiger–Marsden alpha-scattering result: a few alpha particles bounce back at large angles, which rules out Thomson’s diffuse model and demands a tiny, massive, positively charged nucleus. Image: Kurzon, CC BY 3.0, via Wikimedia Commons.
Concept context
Thomson's plum-pudding model, Rutherford's nuclear model from alpha-scattering, Bohr's postulates and hydrogen spectrum, spectral series (Lyman to Pfund), Rydberg formula, and limitations of each model.