The average life time of an electron in an excited state of hydrogen atom is about s. How many revol — Atomic Structure Chemistry Question

💡 Solution & Explanation

For $n=2$, velocity $v = \frac{2.18 \times 10^6}{2} = 1.09 \times 10^6$ m/s, and radius $r = 0.529 \times 4 \text{ \AA} = 2.116 \times 10^{-10}$ m. The time for one revolution is $T = \frac{2\pi r}{v} = \frac{2 \times 3.14 \times 2.116 \times 10^{-10}}{1.09 \times 10^6} \approx 1.2 \times 10^{-15}$ s. Number of revolutions $= \frac{10^{-8}}{1.2 \times 10^{-15}} \approx 8.33 \times 10^6$. Therefore, correct answer is B.