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



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).



It is not possible as it is greater than E.


From n=1 to 3



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



This is possible as E3<E.


From n=2 to 4



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.


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