Questions on Spectral Lines of Hydrogen
20 Multiple-Choice Questions — Spectral Lines of Hydrogen
1. What causes spectral lines in the hydrogen atom?
A) Neutron decay
B) Electron transitions between energy levels
C) Proton collisions
D) Changes in mass
E) Absorption of neutrinos
2. The spectral lines of hydrogen are best explained by which model?
A) Thomson's model
B) Rutherford's model
C) Bohr's model
D) Quantum field theory
E) Dalton's atomic theory
3. When an electron drops from a higher to a lower energy level, what is emitted?
A) Electron
B) Proton
C) Neutron
D) Photon
E) Positron
4. The visible spectral lines of hydrogen belong to which series?
A) Lyman
B) Balmer
C) Paschen
D) Brackett
E) Pfund
5. What type of spectrum is produced by hydrogen gas?
A) Continuous spectrum
B) Emission line spectrum
C) Absorption spectrum
D) Gamma spectrum
E) Infrared spectrum
6. In the hydrogen emission spectrum, the Lyman series lies in which region?
A) Visible
B) Ultraviolet
C) Infrared
D) Microwave
E) Radio
7. Which transition corresponds to the first line of the Balmer series?
A) n=3 → n=2
B) n=2 → n=1
C) n=4 → n=3
D) n=5 → n=1
E) n=2 → n=2
8. What happens to the wavelength of the emitted photon when the energy gap increases?
A) It increases
B) It stays the same
C) It decreases
D) It becomes zero
E) It doubles
9. The Paschen series of hydrogen emission lies in the:
A) X-ray region
B) Ultraviolet region
C) Visible region
D) Infrared region
E) Gamma region
10. Which equation is used to calculate the wavelengths of hydrogen’s spectral lines?
A) Schrödinger equation
B) Einstein’s equation
C) Rydberg formula
D) de Broglie equation
E) Planck's law
11. The value of the Rydberg constant (R_H) is approximately:
A) 1.097 × 10⁷ m⁻¹
B) 3.00 × 10⁸ m/s
C) 6.63 × 10⁻³⁴ J·s
D) 9.11 × 10⁻³¹ kg
E) 1.60 × 10⁻¹⁹ C
12. The energy difference between levels in hydrogen is:
A) Always the same
B) Larger for lower energy levels
C) Smaller for lower energy levels
D) Random
E) Negative only
13. The emission spectrum of hydrogen provides evidence for:
A) Neutrons
B) Electrons having mass
C) Quantized energy levels
D) Proton spin
E) Electron clouds
14. The spectral lines of hydrogen are:
A) Only one color
B) Unique to hydrogen
C) Caused by protons
D) Found in solids
E) Continuous in nature
15. A hydrogen atom in the n=3 level drops to n=1. What is the result?
A) Absorption of energy
B) No radiation
C) High-energy photon emitted
D) Electron ionizes
E) Emission of infrared light
16. What determines the frequency of the emitted light?
A) Electron mass
B) Type of atom
C) Energy difference between levels
D) Speed of light
E) Number of neutrons
17. Which series of hydrogen ends at n=1?
A) Lyman
B) Balmer
C) Paschen
D) Brackett
E) None
18. Why are hydrogen's spectral lines sharp and distinct?
A) Electron clouds overlap
B) Neutron resonance
C) Discrete energy levels
D) High nuclear charge
E) Vibrating protons
19. As electrons move to higher energy levels (excitation), what occurs?
A) Photon emission
B) Ionization
C) Photon absorption
D) Loss of protons
E) Neutron decay
20. Spectral lines of hydrogen helped validate which scientific principle?
A) Law of definite proportions
B) Periodic law
C) Quantum theory
D) Avogadro’s law
E) Law of conservation of mass
- Questions on Photoelectric Effect
- Questions on Atomic Emission Spectra
- Questions on Bohr's Atomic Model
Answers with Extended Explanations
1. B – Electrons transitioning between energy levels emit or absorb photons, producing spectral lines.
2. C – Bohr’s model first explained hydrogen's discrete spectral lines with quantized orbits.
3. D – When an electron drops in energy, it emits a photon of light.
4. B – The Balmer series includes lines in the visible spectrum.
5. B – Excited hydrogen emits an emission line spectrum, not continuous.
6. B – The Lyman series is in the ultraviolet region.
7. A – The transition from n=3 to n=2 is the first line in the Balmer series.
8. C – A larger energy gap corresponds to a shorter wavelength (higher energy photon).
9. D – The Paschen series lies in the infrared part of the spectrum.
10. C – The Rydberg formula predicts hydrogen’s spectral lines.
11. A – The Rydberg constant is 1.097 × 10⁷ m⁻¹, used in spectral calculations.
12. B – Energy gaps are larger between lower energy levels (e.g., n=1 to n=2).
13. C – The discrete lines show that electrons occupy quantized energy levels.
14. B – Hydrogen’s spectral lines are unique and characteristic.
15. C – This large energy drop emits a high-energy (UV) photon.
16. C – The energy difference between levels determines the frequency of light emitted.
17. A – The Lyman series involves transitions ending at n=1.
18. C – Lines are sharp because energy levels are quantized and discrete.
19. C – Photon absorption raises electrons to higher energy states.
20. C – Hydrogen’s spectrum supported the quantum theory of discrete energy levels.
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