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MHT CET 2019 (2 May, Shift 2) · Hydrogen Spectrum & Spectral Series

Hydrogen Spectrum & Spectral Series question from MHT CET 2019 (2 May, Shift 2)

Q50MHT CET 2019 · 2 MAY · SHIFT 2Medium

Hydrogen Spectrum & Spectral Series

In Balmer series, wavelength of first line is ' λ1\lambda_1 ' and in Brackett series wavelength of first line is ' λ2\lambda_2 ' then λ1λ2\frac{\lambda_1}{\lambda_2} is

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Answer: (a)

  1. Balmer first line (3→23 \to 2): 1λ1=R(14−19)=5R36\frac{1}{\lambda_1} = R\left(\frac{1}{4}-\frac{1}{9}\right) = \frac{5R}{36}
  2. Brackett first line (5→45 \to 4): 1λ2=R(116−125)=9R400\frac{1}{\lambda_2} = R\left(\frac{1}{16}-\frac{1}{25}\right) = \frac{9R}{400}
  3. λ1λ2=36/5400/9=3242000=0.162\frac{\lambda_1}{\lambda_2} = \frac{36/5}{400/9} = \frac{324}{2000} = 0.162
  4. So the answer is (a) 0.162.
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