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.
DEFINITION of 'Ratchet Effect' Ratchet effect refers to escalations in production or price that tend to self-perpetuate. Once productive capacities have been added or prices have been raised, it is difficult to reverse these changes, because people tend to be influenced by the previous best or highest level of production. BREAKING DOWN 'Ratchet Effect'