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MHT CET 2026 (20 Apr, Shift 1) · Transitions, Photon Emission & Excitation

Transitions, Photon Emission & Excitation question from MHT CET 2026 (20 Apr, Shift 1)

Q8MHT CET 2026 · 20 APR · SHIFT 1Medium

Transitions, Photon Emission & Excitation

An electron in the hydrogen atom jumps from nthn^{th} energy state to the ground state. The wavelength so emitted illuminates a photosensitive material having work function 2.652.65 eV. If the maximum kinetic energy of the emitted photoelectrons is 10.110.1 eV, then the value of 'nn' is

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Answer: (c)

  1. Photon energy =ϕ+Kmax=2.65+10.1=12.75= \phi + K_{max} = 2.65 + 10.1 = 12.75 eV.
  2. 13.6(1−1n2)=12.75⇒1n2=0.8513.6=11613.6\left(1 - \frac{1}{n^2}\right) = 12.75 \Rightarrow \frac{1}{n^2} = \frac{0.85}{13.6} = \frac{1}{16}
  3. So n=4n = 4, the answer is (c).
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