Answer: v₁/n.
- A v₁/n
- B v₁ × n
- C v₁ × n²
- D v₁/n²
Correct answer: A. v₁/n
Explanation: vn = v₁/n. Speed decreases as orbit number increases. Ground state has highest speed.

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.