Q91 · Practice questionComplex unfamiliar5 marks
QUESTION 91 (5 marks)
The hydrogen energy levels to are shown. Of all possible downward transitions starting from , identify the transition that produces the longest-wavelength photon and calculate that wavelength using the energy values on the diagram.
WORKED SOLUTION
5 marksPractice marking scheme
ANSWER
The longest wavelength is from to , approximately .
Worked solution
Longest wavelength corresponds to the smallest photon energy, because . From the diagram, the smallest downward energy difference from is
Convert to joules:
Then
Identifies smallest energy difference.
Selects n=4 to n=3 transition.
Calculates energy difference.
Uses photon energy relation.
Calculates wavelength.
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