Question
A 12.5 eV electron beam is used to bombard gaseous hydrogen at room temperature. The number of spectral lines emitted will be:
BITSAT
Physics
Atomic Physics
2023
BITSAT 2023 (Memory Based Paper 1)
BITSAT Physics Question (2023) — Solution
Options
- A. 2
- B. 1
- C. 3
- D. 4
Answer
C. 3
Step-by-step solution
If we assume electron in hydrogen atom takes energy 12.09 eV from the incoming radiation, the maximum excited state of electron will be n=3. So, number of spectral lines is 3(3-1) 2 =3. Here we assume some part of energy 12.5 eV -12.09 eV =0.41 eV get lost due to collision.
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