A hydrogen atom, initially at rest in the n = 4 quantum state, undergoes a transition to the ground state, emitting a photon in the process. What is the speed (in terms of m/s) of the recoiling hydrogen atom?(adsbygoogle = window.adsbygoogle || []).push({});

anyone knows what to do? i calculated the energy difference and got 12.75 eV and i calculated the potential energy as well, but i don't know which mass to assign the atom...

any help is appreciated...

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# Homework Help: Energy level problem

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