What is the wavelength of the first line of the Lyman series (n = 2 to n = 1) (R = 1.097 × 10⁷ m⁻¹)?
Correct answer A. 122 nm
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Atomic Spectra MCQs
Atomic Spectra MCQs cover continuous and line spectra, emission and absorption spectra, the energy levels of the hydrogen atom and its spectral series such as Lyman, Balmer and Paschen. They suit MDCAT, ECAT and FSc revision, and every question on MCQs360 shows its correct answer instantly so you can check each step.
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What is the angular momentum of an electron in the second Bohr orbit of hydrogen (h = 6.63 × 10⁻³⁴ J s)?
Correct answer C. 2.11 × 10⁻³⁴ J s
What is the ratio of the wavelength of the first Lyman line (n = 2 to 1) to that of the first Balmer line (n = 3 to 2)?
Correct answer B. 0.185
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The radius of the first Bohr orbit of hydrogen is 0.053 nm. What is the radius of the third orbit (rₙ = n²r₁)?
Correct answer D. 0.477 nm
What is the minimum energy needed to raise a hydrogen atom from its ground state to its first excited state (Eₙ = −13.6/n² eV)?
Correct answer A. 10.2 eV
How much energy is needed to ionise a hydrogen atom whose electron is in the n = 2 level (Eₙ = −13.6/n² eV)?
Correct answer D. 3.4 eV
Hydrogen atoms are excited to the n = 4 level. How many different spectral lines can be emitted as they return to the ground state?
Correct answer B. 6
What is the wavelength of the series limit of the Balmer series (R = 1.097 × 10⁷ m⁻¹)?
Correct answer B. 365 nm
What is the wavelength of the series limit of the Lyman series (R = 1.097 × 10⁷ m⁻¹)?
Correct answer D. 91.2 nm
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Using the Rydberg formula, what is the wavelength of the first Balmer line (n = 3 to n = 2) (R = 1.097 × 10⁷ m⁻¹)?
Correct answer D. 656 nm
The shortest wavelength line in any series of the hydrogen spectrum corresponds to a transition from ____
Correct answer A. n = ∞ to the final level of that series
What energy photon is emitted when an electron in hydrogen falls from n = 3 to n = 2 (Eₙ = −13.6/n² eV)?
Correct answer B. 1.89 eV
What is the energy of the n = 3 level of a hydrogen atom (Eₙ = −13.6/n² eV)?
Correct answer B. −1.51 eV
The dark Fraunhofer lines seen in the spectrum of sunlight are caused by ____
Correct answer D. absorption by cooler gases in the Sun's outer atmosphere
Why do the dark lines in the absorption spectrum of a gas occur at the same wavelengths as the bright lines in its emission spectrum?
Correct answer A. Both involve the same differences between energy levels
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How does the spacing between successive energy levels of hydrogen change as n increases?
Correct answer D. It decreases
According to Bohr’s model, the angular momentum of an electron in an allowed orbit is ____
Correct answer A. an integral multiple of h/2π
What is the ionisation energy of a hydrogen atom in its ground state?
Correct answer C. 13.6 eV
What is the energy of an electron in the ground state of a hydrogen atom?
Correct answer B. −13.6 eV
An atom emits a photon when one of its electrons ____
Correct answer D. moves from a higher level to a lower level
About Atomic Spectra MCQs
Questions begin with the types of spectra: which sources give continuous spectra and which give line spectra, and why the dark lines of an absorption spectrum match the bright lines of the emission spectrum of the same gas. Energy-level questions use Eₙ = −13.6/n² eV to find the energy of a level, the energy needed for excitation or ionisation and the energy of photons emitted when electrons fall between levels. Series questions ask in which region of the spectrum the Lyman, Balmer and Paschen series lie and which transitions produce them.
Key facts to remember
- Energy levels of hydrogen: Eₙ = −13.6/n² eV, so E₁ = −13.6 eV, E₂ = −3.4 eV and E₃ ≈ −1.51 eV.
- A photon emitted or absorbed in a transition has energy hf = Eᵢ − E_f.
- Ionisation energy of hydrogen from the ground state is 13.6 eV; excitation from n = 1 to n = 2 needs 10.2 eV.
- Lyman series (transitions to n = 1) is ultraviolet, Balmer (to n = 2) is visible, and Paschen (to n = 3) is infrared.
- Hot solids and dense gases give continuous spectra; hot low-pressure gases give line spectra characteristic of the element.
- Rydberg formula: 1/λ = R_H(1/p² − 1/n²), with R_H ≈ 1.097 × 10⁷ m⁻¹.
Exams that include Atomic Spectra MCQs
Pakistan
- MDCAT
- ECAT (UET)
- NUMS
- AKU
- FSc boards
India
- NEET
- JEE Main
Bangladesh
- HSC
- Medical Admission Test
How to prepare for Atomic Spectra MCQs
- Write out the first four hydrogen energy levels; most calculations are simple subtractions between them.
- Remember that ionisation from level n needs +13.6/n² eV, the energy to raise the electron to zero.
- Link each series to its lower level and region: Lyman–1–UV, Balmer–2–visible, Paschen–3–infrared.
- Emission happens when an electron falls to a lower level; absorption when it rises to a higher one.
Frequently asked questions
Which exams ask Atomic Spectra MCQs?
Atomic Spectra is part of the FSc physics syllabus, so its MCQs appear in MDCAT, ECAT (UET), NUMS and AKU entry tests and in FSc board papers. Students in India meet the same ideas in NEET and JEE Main, and Bangladeshi students in HSC and the medical admission test.
Why do absorption and emission lines occur at the same wavelengths?
Both come from the same energy levels. An atom absorbs a photon only if its energy matches the gap between two levels, and emits a photon of the same energy when the electron falls back. So the dark absorption lines of a gas sit exactly where its bright emission lines appear.
Last reviewed October 2026