Radiation coming from transitions n = 2 to n = 1 of hydrogen atoms falls on helium ions in n = 1 and n = 2 states. What are the possible transitions of helium ions as they absorb energy from the radiation?
Radiation coming from change in transition state of hydrogen atom
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Now we have to check transition possible for n=1 and n=2 states separately.
From n = 1 to 2 for helium ions(Z=2).
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It is not possible as it is greater than E.
From n=1 to 3
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It is also not possible.
Now as we can see energy is increasing (E2>E1) we can say that no transition is possible from n=1.
From n=2 to 3
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This is possible as E3<E.
From n=2 to 4
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It is also possible as E4=E.
Now as energy reached maximum limit so no further transition changes is possible.
Hence E3(n=2 to 3) and E4(n=2 to 4) are only possible transition change.