Why does a nurse needed a red pen

Back in the day, because nurses would use pens to write notes , and before computers were used for charting our “nurses notes”, many nurses would carry or use different colors of ball point pen ink to indicate which time of day or night it was. Red was commonly used, years ago, to denote the night or overnight shift.

Explanation:

i got this from https://www.quora.com/Why-do-nurses-use-a-red-pen

beta is electron from nucleus

something from nucleus has changed, but charge must be same for cons of charge