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JEE Main 2022 (27 Jun, Shift 1) · Transitions, Photon Emission & Excitation

Transitions, Photon Emission & Excitation question from JEE Main 2022 (27 Jun, Shift 1)

Q43JEE Main 2022 · 27 JUN · SHIFT 1Medium

Transitions, Photon Emission & Excitation

A beam of monochromatic light is used to excite the electron in Li++ from the first orbit to the third orbit. The wavelength of monochromatic light is found to be x ×\times 10−-10 m. The value of x is ___________.

[Given hc = 1242 eV nm]

Numerical answer type. Work it out, then open the answer.

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Answer: 114

  1. For Li++^{++}, Z=3Z = 3: ΔE=13.6×9×(1−19)=108.8\Delta E = 13.6 \times 9 \times \left(1 - \frac{1}{9}\right) = 108.8 eV
  2. λ=hcΔE=1242108.8\lambda = \frac{hc}{\Delta E} = \frac{1242}{108.8} nm =11.4= 11.4 nm
  3. λ=114×10−10\lambda = 114 \times 10^{-10} m, so x=114x = 114.
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