The diagram shows an energy level diagram for a hydrogen atom - AQA - A-Level Physics - Question 12 - 2017 - Paper 1
Question 12
The diagram shows an energy level diagram for a hydrogen atom.
Electrons with energy 13.0 eV collide with atoms of hydrogen in their ground state.
What is the numb... show full transcript
Worked Solution & Example Answer:The diagram shows an energy level diagram for a hydrogen atom - AQA - A-Level Physics - Question 12 - 2017 - Paper 1
Step 1
Determine the energy levels reachable from ground state
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Answer
The ground state of hydrogen is at -13.6 eV. The incoming electrons have 13.0 eV. The maximum energy level that an electron can reach is calculated as follows:
Energy level = initial energy + energy of incoming electron = -13.6 eV + 13.0 eV = -0.6 eV.
From the energy level diagram:
Level 1: -13.6 eV
Level 2: -3.4 eV
Level 3: -1.51 eV
Level 4: -0.85 eV
The electron can transition to levels 2, 3, and 4 from the ground state.
Step 2
Calculate the possible transitions
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Answer
The number of unique transitions that can occur from each attainable excited state level back to the ground state is:
From level 4 to level 1
From level 3 to level 1
From level 2 to level 1
Plus transitions between levels 4, 3, and 2 to each other.
The total transitions possible from 3 excited states:
3 levels can emit to 1 common ground state, and from levels they can emit different wavelengths.
Thus, the combination of transitions is 3, meaning that the number of different wavelengths is 3.
Step 3
Final answer choice
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Answer
The correct answer is B (3 different wavelengths of electromagnetic radiation can be emitted).