The formula for a half-life is T12 ln 2 l. We will raise that by the number of years divided by the number of years in the half-life. Furthermore it refers to the time that a particular quantity requires to reduce its initial value to half.
Half-Life For a substance decaying exponentially the amount of time it takes for the amount of the substance to diminish by half.
This concept is quite common in nuclear physics and it describes how quickly atoms would undergo radioactive decay. The term is most commonly used in relation to atoms undergoing radioactive decay but can be used to describe other types of decay whether exponential or not. Measuring the rate of decay of a particular substance half-life is the time taken by a given amount of the substance to decay to half its mass. In this equation T12 is the half-life.