Easy MCQ +4 / -1 PYQ · JEE Mains 2023

Speed of an electron in Bohr's $7^{\text {th }}$ orbit for Hydrogen atom is $3.6 \times 10^{6} \mathrm{~m} / \mathrm{s}$. The corresponding speed of the electron in $3^{\text {rd }}$ orbit, in $\mathrm{m} / \mathrm{s}$ is :

  1. A $\left(1.8 \times 10^{6}\right)$
  2. B $\left(7.5 \times 10^{6}\right)$
  3. C $\left(8.4 \times 10^{6}\right)$ Correct answer
  4. D $\left(3.6 \times 10^{6}\right)$

Solution

<p>$v\,\alpha {z \over n}$</p> <p>${{{v_1}} \over {{v_2}}} = \left( {{{{n_2}} \over {{n_1}}}} \right)$</p> <p>$\Rightarrow {{3.6 \times {{10}^6}} \over {{v_2}}} = {3 \over 7}$</p> <p>$\Rightarrow {v_2} = {7 \over 3} \times 3.6 \times {10^6}$ m/s</p> <p>$= 8.4 \times {10^6}$ m/s</p>

About this question

Subject: Physics · Chapter: Atoms and Nuclei · Topic: Bohr's Model of Hydrogen Atom

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