Free Atomic Spectra MCQs with Answers
356 Atomic Spectra MCQs from Physics, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
Atoms emit or absorb light at specific wavelengths because electrons occupy quantized energy levels and change levels by absorbing or releasing photons. The topic covers emission and absorption spectra, spectral series, hydrogen’s line spectrum, energy-level transitions, and the relation between wavelength, frequency and photon energy.
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Read the Atomic Spectra notesFree MDCAT chapter notes with key terms356 questions · page 4 of 18
- A. Option A
- B. Option B
- C. Option C
- D. Option D
Explanation: Both gain the same kinetic energy (eV), so their de-Broglie wavelength depends only on mass:λ = h / √(2m eV)Taking the ratio:λₑ / λₚ =…
Correct answer: Option D- A. RH = Eo/hc
- B. Eo = RH/hc
- C. RH = hc/Eo
- D. RH =Eohc
Explanation: From the ground-state energy E0=−hcRH you can rearrange it to get RH = Eo/hc.
Correct answer: RH = Eo/hc- A. 16/R
- B. 16RH
- C. RH/16
- D. 4/RH
Explanation: In the Brackett series, all transitions end at n = 4. The shortest wavelength comes from the transition n → ∞ → 4 (the series limit).
Correct answer: 16/R- A. 1/2
- B. 1
- C. 1/4
- D. 2
Explanation: Photon energy is directly proportional to frequency, so doubling the frequency doubles the energy. That means the ratio (EA/EB) is 2 : 1.
Correct answer: 2- A. Option A
- B. Option B
- C. Option C
- D. Option D
Explanation: Figure show that the radiation of most energy is emitted when electron jumps from n=2 orbit to n= 1 orbit
Correct answer: Option B- A. Visible region
- B. Ultraviolet region
- C. Infrared region
- D. X-ray region
Explanation: The Paschen series consists of transitions where the electron falls to n = 3 from higher levels (n ≥ 4).
Correct answer: Infrared region- A. 6.63 x 10^-34 js-1
- B. 6.63 x 10^-43 js
- C. 6.63 x 10^-34 js
- D. 3.63 x 10^-34 js
Explanation: The value of Planck's constant is 6.626 × 10⁻³⁴, and its unit is joule-seconds (J·s).
Correct answer: 6.63 x 10^-34 js- A. mv
- B. mc
- C. hf
- D. hf/c
Explanation: The momentum of a photon is given by the formula p = hf/c, where h is Planck's constant, f is the frequency of the photon, and c is the…
Correct answer: hf/c- A. Option A
- B. Option B
- C. Option C
- D. Option D
Explanation: The series limit of the Lyman series corresponds to the photon emitted when an electron reaches the first energy level from very high…
Correct answer: Option C- A. Small
- B. Large
- C. Average
- D. Does not depend of wavelength
Explanation: As mentioned in the explanation for option A, when the uncertainty in measuring the position of a particle is small, the wavelength of the…
Correct answer: Small- A. Option A
- B. Option B
- C. Option C
- D. Option D
Explanation: The de Broglie wavelength of a particle is inversely related to its momentum, and momentum depends on the square root of kinetic energy.
Correct answer: Option C- A. Moving charged particles only
- B. Moving neutral particles only
- C. All moving particles
- D. All particles whether in motion or at rest
Explanation: De-Broglie waves are associated with moving charged particles, such as electrons and other charged particles, according to Louis de…
Correct answer: Moving charged particles only- A. Uncertainty Principle
- B. Einstein's Theory
- C. De-Broglie Theory
- D. Photoelectric effect
Explanation: The uncertainty principle is the concept that tells us that, due to the intrinsic nature of quantum mechanics, we cannot accurately…
Correct answer: Uncertainty Principle- A. 10.2 eV
- B. 3.4 eV
- C. 0 eV
- D. 6.8 eV
Explanation: Ionizing a hydrogen atom from its ground state requires 13.6 eV. For an electron in the second orbit, it's already at a higher energy…
Correct answer: 3.4 eV- A. Option A
- B. Option B
- C. Option C
- D. Option D
Explanation: In Bohr's model, the kinetic energy of an electron is given by ½ × (Ze² / r), where Z is the atomic number, e is the electron charge, and…
Correct answer: Option A- A. Option A
- B. Option B
- C. Option C
- D. Option D
Explanation: According to Bohr's theory radius of quantized orbit is given by: r = n2h2/4π2mZe2.
Correct answer: Option C- A. Number of electrons striking target
- B. Nature of the target
- C. Accelerating potential
- D. both b and c
Explanation: The frequency of X-rays depends on the accelerating potential (voltage) applied to the X-ray tube.
Correct answer: both b and c- A. High atomic number and high melting point
- B. High atomic number and low melting point
- C. Low atomic number and low melting point
- D. Coherent beam of light
Explanation: Target materials in X-ray tubes should have a high atomic number because X-ray production is more efficient when interacting with high…
Correct answer: High atomic number and high melting point- A. Option A
- B. Option B
- C. Option C
- D. Option D
Explanation: For hydrogen, the radius of the first orbit is given by the formula:r=h2 /4pi2me2where (h) is Planck's constant, (m) is the electron mass…
Correct answer: Option B- A. First orbit
- B. Third orbit
- C. Second orbit
- D. Fourth orbit
Explanation: Bracket series is obtained when all transitions of electron terminate at p=4 .
Correct answer: Fourth orbit