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Question: Answered & Verified by Expert
In the Bohr model of a hydrogen atom, the centripetal force is furnished by the coulomb attraction between the proton and the electron. If $a_{0}$ is the radius of the ground state orbit, $m$ is the mass and e is charge on the electron and $\varepsilon_{0}$ is the vacuum permittivity, the speed of the electron is
PhysicsMagnetic Properties of MatterVITEEEVITEEE 2010
Options:
  • A 0
  • B $\frac{\mathrm{e}}{\sqrt{\varepsilon_{0} \mathrm{a}_{0} \mathrm{~m}}}$
  • C $\frac{\mathrm{e}}{\sqrt{4 \pi \varepsilon_{0} \mathrm{a}_{0} \mathrm{~m}}}$
  • D $\frac{\sqrt{4 \pi \varepsilon_{0} \mathrm{a}_{0} \mathrm{~m}}}{\mathrm{e}}$
Solution:
2057 Upvotes Verified Answer
The correct answer is: $\frac{\mathrm{e}}{\sqrt{4 \pi \varepsilon_{0} \mathrm{a}_{0} \mathrm{~m}}}$
Centripetal force $=$ force of attraction of nucleus on electron.
$$
\frac{m v^{2}}{a_{0}}=\frac{1}{4 \pi \varepsilon_{0}} \cdot \frac{e^{2}}{a_{0}^{2}} \Rightarrow v=\frac{e}{\sqrt{4 \pi \varepsilon_{0} m a_{0}}}
$$

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