Photons emitted between energy levels?

[CAH]

See photo attachment! (question 1(b) and see answer on mark scheme underneath)

How can three photons be emitted? Either the electron drops down from 3 to 1 and skips 2 emitting one big 12.1 eV photon OR it falls down in step emitting two photons 1.9eV and 10.2eV. How can it emit more energy than its been given anyway?

Thanks

 

[DrClaude]

The question is not well formulated. It isn't that a single collision with a single atom will give off three photons, but rather that following the collision three possible photon energies can be observed.

 

[CAH]

Exactly what I thought, just cheaking... thanks