If the lowest energy X-rays have λ = 3.055×10⁻⁸ m, estimate the minimum Z at which a transition from n=2 to n=1 would emit an X-ray.
Correct answer: A. Z=2
- A. Z=2
- B. Z=3
- C. Z=4
- D. Z=5
Explanation
First, the energy of the X-ray is calculated as E = hc/λ ≈ 40.6 eV. The energy of the n=2 to n=1 transition is ΔE = 10.2 Z². Setting 10.2 Z² = 40.6 and solving for Z gives Z ≈ 2. The minimum integer atomic number is 2.
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