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Question: Answered & Verified by Expert
An electron with kinetic energy $E$ collides with a hydrogen atom in the ground state. The collision will be elastic
PhysicsCenter of Mass Momentum and CollisionKVPYKVPY 2016 (SB/SX)
Options:
  • A For all values of $E$
  • B For $10.2 \mathrm{eV} < \mathrm{E} < 13.6 \mathrm{eV}$ only
  • C For $\mathrm{E} < 10.2 \mathrm{eV}$
  • D For $0 < \mathrm{E} < 3.4 \mathrm{eV}$ only
Solution:
2965 Upvotes Verified Answer
The correct answer is: For $10.2 \mathrm{eV} < \mathrm{E} < 13.6 \mathrm{eV}$ only
When $\mathrm{e}^{-}$collide with atom which is massive in comparison to $\mathrm{e}^{-} .$Max possible loss of $\mathrm{KE}=\mathrm{KE}$ of $\mathrm{e}^{-}($initial $\mathrm{KE})=\mathrm{E}$ if this $\mathrm{E}$ is less than min excitation energy then collision is elastic
$\therefore \mathrm{E} < 10.2 \mathrm{eV}$ (Minimum excitation energy)

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