Gce Model Questions Vol1 2021 Physics Question 32
Practice objective / multiple choice question 32 from the 2021 Gce Model Questions Vol1 Physics examination.
A beam of electrons is accelerated through a potential difference \(V\) and directed at stationary hydrogen atoms. The electrons have just enough kinetic energy to excite the atoms from the ground state \(n=1\) to the \(n=4\) level. The excited atoms subsequently decay to \(n=2\), emitting the Balmer‑α photon (rest wavelength \(\lambda_{0}=656.3\) nm). Because the emitting atoms recoil, the observed wavelength is \(\lambda=656.32\) nm (a red shift of \(0.02\) nm). Assuming non‑relativistic recoil, determine the minimum accelerating potential \(V\) (in volts) required. Use \(m_{H}=1.67\times10^{-27}\) kg and \(c=3.00\times10^{8}\) m s⁻¹. Give \(V\) to two significant figures.
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About This Question
This is Gce Model Questions Vol1 2021 Physics Question 32. It is one of the objective questions from the 2021 Gce Model Questions Vol1 Physics examination.
Difficulty level: Hard .
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