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MHT CET 2026 (19 Apr, Shift 1) · Hydrogen Spectrum & Spectral Series

Hydrogen Spectrum & Spectral Series question from MHT CET 2026 (19 Apr, Shift 1)

Q7MHT CET 2026 · 19 APR · SHIFT 1Medium

Hydrogen Spectrum & Spectral Series

The shortest wavelength in the Balmer series of hydrogen atom is equal to the shortest wavelength in the Brackett series of a hydrogen like atom of atomic number 'Z'. The value of 'Z' is

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Answer: (d)

  1. Shortest λ\lambda = series limit: 1λ=RZ2n12\frac{1}{\lambda} = \frac{RZ^2}{n_1^2}.
  2. H Balmer: λ=4R\lambda = \frac{4}{R}. Brackett (n1=4n_1 = 4) for atomic number ZZ: λ=16RZ2\lambda = \frac{16}{RZ^2}.
  3. 4R=16RZ2⇒Z2=4⇒Z=2\frac{4}{R} = \frac{16}{RZ^2} \Rightarrow Z^2 = 4 \Rightarrow Z = 2.
  4. So the answer is (d) 22.
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