CBSE 2026 · Region 4 · Set 2 · Q24 · 3 marks
In Bohr model of hydrogen atom, calculate :(a)the radius of the innermost electron orbit, and(b)the speed of electron in this orbit.
In Bohr model of hydrogen atom, calculate :
(a)
the radius of the innermost electron orbit, and
(b)
the speed of electron in this orbit.
Marking-scheme solution
(a)
(b)
Calculating speed of electron in the same orbit.
(a)
The radius of innermost electron orbit is given by,
\[\mathrm{r}=-\frac{\mathrm{e}^{2}}{8 \pi \varepsilon_{0} \mathrm{E}} \quad-\ldots--(1)
\]
where $\displaystyle \mathrm{E}=$ Energy of electron in hydrogen atom in innermost orbit ( $\displaystyle \mathrm{n}=1$ ).
Using formula, $\displaystyle \mathrm{E}_{\mathrm{n}}=-\frac{13.6}{\mathrm{n}^{2}} \mathrm{eV}$
AtomsBohr Model of the Hydrogen AtomApplyshort_answereasy
More from Atoms
- The radius of the n^ th orbit in Bohr model of hydrogen atom is proportional to2023 · asked 4×
- Assertion: An alpha particle is moving towards a gold nucleus. The impact parameter is maximum for the…2024 · asked 3×
- Draw the graph showing the variation of the number (N) of scattered alpha particles with scattering angle ( θ…2022 · asked 3×
- Hydrogen atom initially in the ground state, absorbs a photon which excites it to n=5 level. The wavelength…2023 · asked 3×
- The transition of electron that gives rise to the formation of the second spectral line of the Balmer series…2024 · asked 3×
- Draw the graph showing variation of scattered particles detected ( N ) with the scattering angle ( θ ) in…2024 · asked 3×
- Energy levels A, B and C of an atom correspond to increasing values of energy i.e. E A<E B<E C. Let λ 1, λ 2…2024 · asked 3×
- In Balmer series of hydrogen atom, as the wavelength of spectral lines decreases, they appear2024 · asked 3×
CBSE Class 12 Physics past-paper question from the 2026board exam, with the answer as CBSE’s own marking scheme gives it. Where our answers come from.