MDCAT Atomic Spectra MCQs

Sample Atomic Spectra MCQs with answers

Try these questions, then open the answer to check your reasoning. Use the quiz above for more topics and a complete review.

1. Line Spectra

   1. Which of the following is not true?

   1. A. The Lyman series is a continuous spectrum
   2. B. The Ballmer series is a line spectrum in the visible region
   3. C. The Paschen series is a line spectrum in the infrared region
   4. D. The spectral series formula can be derived from Rutherford’s model of the hydrogen atom 18. The photoelectric effect is the ejection of
   View answer and explanation

   Answer: A. The Lyman series is a continuous spectrum

   All hydrogen spectral series (Lyman, Balmer, Paschen) are discrete line spectra produced by electron transitions between fixed energy levels, not continuous spectra that contain every wavelength. The Lyman series lies in the ultraviolet region and is a line spectrum like the others, so describing it as a continuous spectrum is the one statement that is not true. The remaining options correctly identify line spectra and their spectral regions, which is why only A is the answer to this not-true question.

2. Line Spectra

   2. For the hydrogen transition $n=4$ to $n=3$, the emitted photon frequency is:

   1. A. 1.600e+ $14\mathrm{Hz}$
   2. B. 1.600e+ $13\mathrm{Hz}$
   3. C. 1.600e+ $15\mathrm{Hz}$
   4. D. 6.251e- $15\mathrm{Hz}$
   View answer and explanation

   Answer: A. 1.600e+ $14\mathrm{Hz}$

   After finding $\lambda$ from the Rydberg relation, $f=c/\lambda$ = 1.600e+ $14\mathrm{Hz}$.

3. Line Spectra

   3. According to electromagnetic theory, the frequency of the spectral line emitted by the vibrating electron should be

   1. A. Same as the electron
   2. B. Infinity
   3. C. Less than the electron
   4. D. Greater than the electron
   View answer and explanation

   Answer: A. Same as the electron

   Classical electromagnetic theory predicted that an oscillating electron radiates at the same frequency as its own vibration, so the emitted spectral line should match the electron's oscillation frequency. The infinity/greater/lesser options contradict this classical result.