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Question: Answered & Verified by Expert
In a hydrogen sample, if the atoms are excited to states with principal quantum number 20 , then the number of different wavelengths which may be observed in the spectrum is
PhysicsAtomic PhysicsTS EAMCETTS EAMCET 2018 (07 May Shift 1)
Options:
  • A 100
  • B 140
  • C 190
  • D 230
Solution:
1152 Upvotes Verified Answer
The correct answer is: 190
When atom are excited from ground state to excited state with $n=20$, then number of spectral line possible are
$=\frac{n(n-1)}{2}$ [where, $n=$ principal quantum number]
$=\frac{20(20-1)}{2}=190$

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