Answer: Electron e3 must emit a photon of light in order to drop down from the n=5 to the n=4 energy level.
Step-by-step explanation:
When an electron drops from a higher energy level to a lower energy level, it releases energy. This energy is emitted in the form of a photon, which is a particle of light. The wavelength of the photon is determined by the difference in energy between the two energy levels.
In this case, the electron is dropping from the n=5 energy level to the n=4 energy level. The difference in energy between these two levels is 2.18 eV. So, the photon that is emitted will have a wavelength of 121.6 nanometers.
The emission of a photon by an electron is a quantum mechanical process. This means that it cannot be predicted exactly when the electron will emit the photon. However, it is possible to calculate the probability of the electron emitting the photon at a given time.
The probability of the electron emitting the photon is greatest when the electron is in the n=5 energy level. As the electron falls to the n=4 energy level, the probability of emitting the photon decreases.
The emission of a photon by an electron can be used to study the structure of atoms and molecules. It can also be used to generate light of a specific wavelength, which is useful in a variety of applications, such as lasers and spectroscopy.