<span>Energy is absorbed and then released to form an emission line.
When electrons absorb energy they increase there energy level. This is only temporary and the excited electron then relaxes back down to its original energy level releasing energy.
The energy is released in form of EM radiation of a specific frequency depending on the element and how many energy levels the electron relaxes.
This forms an emission line.</span><span />
Answer:
90.46 well that's how I got the answer from my calculations
For a closed system, you need two things:
1) a conservation of mass within the boundaries of the system
2) the ability to freely exchange energy to & from the "closed" system with a surrounding external system
So, the answer is <u><em>never</em></u>, since your defining the "system" as the water within the bathtub, and an open bathtub is exposed to evaporation, which is not conserving mass within the defined "system".
