The answer is never because there's no electricity
Well, all of this we owe it to Bohr who analyzed the atomic emission spectrum of hydrogen and he could probe matematically that it was a result of movement of e- from an especific energy level to a lower one. The understanding of levels of energy took to the development of the atomic theory
Answer:
The element that glows in signs is xenon.
Explanation:
Xenon is a chemical element with the symbol Xe and atomic number 54. It is a colorless, dense, odorless noble gas found in Earth's atmosphere in trace amounts. Xenon is used in flash lamps, arc lamps, and as a general anesthetic. Xenon emits a blue or lavenderish glow when excited by electrical discharge, it emits a band of emission lines that span the visual spectrum, but the most intense lines occur in the region of blue light, producing the coloration.