Final answer:
The release of red light is caused by an electron transitioning from a higher to a lower energy state, releasing a photon with energy corresponding to a longer wavelength such as 694.3 nm for a ruby laser.
Step-by-step explanation:
The change in quantum states that results in the release of red light is a transition from a higher-energy orbital to a lower-energy orbital. When an electron in an atom falls from a higher energy state to a lower energy state, energy is released in the form of a photon.
The amount of energy released corresponds to the difference in energy between the two states and can be calculated using Planck's constant (E = hv), where h is Planck's constant and v is the frequency of the light.
Since the frequency is inversely proportional to the wavelength, longer wavelengths such as red light correspond to a lower energy transition compared to shorter wavelengths like blue or violet light.
In the case of the red light emitted by a ruby laser at a wavelength of 694.3 nm, the electron transition that causes the emission would release less energy than transitions associated with higher-energy photons such as blue or violet light.