You can't see germs with a black light, but might be able to see thick lotion.
Black lights do not show germs directly. They can make certain substances, like some bodily fluids or certain materials, glow under ultraviolet light, but this is not a reliable method for detecting germs. To see germs, you would need a microscope or other specific testing methods.
More germs are in the hair than hands!
From dirty things, direct contact(from other people) and others.
A person has more germs in their mouth than on their hands. Saliva has enzymes that prevent germs from forming, while your hands touch things such as doorknobs all day which are infested with germs.
The germs on your hands will spread to every surface you touch. So the door handle in the bathroom will be full of germs. Any one who touches it after that will take some of the germs with them. everything they touch will also leave some germs behind. Also if you touch someone else you will pass germs to them as well.
Billions.
by not washing hands ?
Black lights do not reveal the presence of germs. They are used to detect certain substances that fluoresce under ultraviolet light, but they do not specifically indicate the presence of germs.
No
yes!
The life span of germs on hands can vary depending on the type of germ and the conditions present. Generally, some germs can survive on hands for a few hours up to a few days. Regular handwashing with soap and water is important to reduce the transmission of germs.
I almost think you are kidding. Everything you touch, all day, every day, puts germs on your hands.