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QJEEM19Pha25f: JEE Main 2019 Physics - Class 12 JEEM19Pha25f Solution: In Li + + , electron in first Bohr orbit is excited to a level…

In Li+ +, electron in first Bohr orbit is excited to a level by a radiation of wavelength λ\lambda . When the ion gets deexcited to the ground state in all possible ways (including intermediate emissions), a total of six spectral lines are observed. What is the value of λ\lambda ?
(Given : H = 6.63 × 10–34 Js; c = 3 × 108 ms –1)

Multiple Choice Options

  • A 10.8 nm
  • B 12.3 nm
  • C 9.4 nm
  • D 11.4 nm

Step-by-Step Verified Solution

JEE Main 2019 (Online) 10th April Evening Slot Physics - Atoms and Nuclei Question 186 English Explanation hcλ=13.6 ev(g){1−116}{{hc} \over \lambda } = 13.6\,ev(g)\left\{ {1 - {1 \over {16}}} \right\}

1240 eVλ=1516×9×13.6 eV{{1240\,eV} \over \lambda } = {{15} \over {16}} \times 9 \times 13.6\,eV

λ=1240×1615×9×13.6=10.8 nm\lambda = {{1240 \times 16} \over {15 \times 9 \times 13.6}} = 10.8\,nm

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