The rule is that a sample is safe when its radioactivity has dropped below detection limits. And that occurs at 10 half-lives. So, if radioactive iodine-131 (which has a half-life of 8 days) is injected into the body to treat thyroid cancer, itâll be âgoneâ in 10 half-lives, or 80 days.
The term 'ratchet' has no less than two distinct meanings. As an adjective, it describes a person, usually a woman, or activity, who is out of hand, out of control, generally whack in some way, dirty, ghetto, unattractive, Crucian, or just generally disliked.
verb. A grey rat. A grey rat. The definition of a rat is a rodent with a lengthy tail, or is slang for a sneaky person. 1  An example of a rat is a roof rat.2  An example of a rat is a person who plays mean tricks on his coworkers.plural rats). ( 1 zoology) A medium-sized rodent belonging to the genus Rattus. ( 2 informal) A term indiscriminately applied to numerous members of several rodent families (e.g. voles and mice) having bodies longer than about 12 cm, or 5 inches. ( 3 informal) A person who is known for betrayal; a scoundrel; a quisling.