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Question
For a given material, the energy and wavelength of characteristic X-rays satisfy
(a) E(Kα) > E(Kβ) > E(Kγ)
(b) E(Mα) > E(Lα) > E(Kα)
(c) λ(Kα) > λ(Kβ) > λ(Kγ)
(d) λ(Mα) > λ(Lα) > λ(Kα).
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Solution
(c) λ(Kα) > λ(Kβ) > λ(Kγ)
(d) λ(Mα) > λ(Lα) > λ(Kα)
The Kγ transition (from the N shell to the K shell) involves more energy than the Kβ transition (from the M shell to the K shell), which has more energy than the Kα transition (from the L shell to the K shell).
As the energy varies inversely with the wavelength,
λ(Kα) > λ(Kβ) > λ(Kγ)
The Mα transition is due to the jumping of an electron from the N shell to the M shell and involves less energy than the Lα transition (from the M shell to the L shell), which involves less energy than the Kα transition (from the L shell to the K shell).
As the energy varies inversely with the wavelength,
λ(Mα) > λ(Lα) > λ(Kα)
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