Statement I: According to Bohr's model of an atom, qualitatively the magnitude of velocity of electron increases with…

🧠 Dynamics of the Bohr Electron Bohr's velocity ($v_n$) is a balance of centrifugal force and nuclear attraction. The speed depends on how strong the "pull" is ($Z$) and how "far" the path is ($n$).

🗺️ The Velocity Audit

• Statement I: Claims velocity increases with decrease in positive charge ($Z$).
  • Check: $v \propto Z/n$. If $Z$ decreases, the pull is weaker, and the speed decreases. So, Statement I is False.
• Statement II: Claims velocity increases with decrease in principal quantum number ($n$).
  • Check: As $n$ decreases (electron gets closer to nucleus), the orbital speed must increase to stay in balance. $v \propto 1/n$. So, Statement II is True.

⚡ The Satellite Analogy Think of planets! Planets closer to the Sun ($n$ is small) move much faster than distant ones. And a massive Sun ($Z$ is large) makes planets move faster. $V = \text{Large } Z, \text{ Small } n$.

⚠️ Common Traps Qualitative distractors! Words like "no strong hold" in I sounds plausible, but the mathematical proportionality $v \propto Z$ is absolute. Don't let the physical "story" distract you from the formula.

$\boxed{\text{Answer: (a)}}$