How To Find Half Life From A Graph

One-half-Life Figurer

The following tools can generate whatsoever one of the values from the other 3 in the half-life formula for a substance undergoing disuse to decrease by half.

Half-Life Calculator

Please provide whatever three of the following to calculate the fourth value.

quantity remains N_t	initial quantity Northward₀	fourth dimension t	half-life t_one/2

One-half-Life, Mean Lifetime, and Decay Abiding Conversion

Delight provide any one of the post-obit to get the other two.

half-life t_1/two		mean lifetime τ		decay constant λ
	=		=

Definition and Formula

Half-life is defined as the amount of time it takes a given quantity to decrease to half of its initial value. The term is most unremarkably used in relation to atoms undergoing radioactivity, but tin be used to depict other types of disuse, whether exponential or not. Ane of the most well-known applications of half-life is carbon-fourteen dating. The half-life of carbon-14 is approximately 5,730 years, and it can be reliably used to mensurate dates up to around 50,000 years ago. The process of carbon-14 dating was adult by William Libby, and is based on the fact that carbon-fourteen is constantly existence fabricated in the atmosphere. It is incorporated into plants through photosynthesis, and and then into animals when they consume plants. The carbon-xiv undergoes radioactivity one time the constitute or animal dies, and measuring the amount of carbon-fourteen in a sample conveys information about when the plant or animal died.

Beneath are shown 3 equivalent formulas describing exponential decay:

N₀

N_t

t_1/2

If an archeologist institute a fossil sample that contained 25% carbon-14 in comparing to a living sample, the time of the fossil sample's death could be determined by rearranging equation 1, since N_t , Due north₀ , and t_1/2 are known.

This means that the fossil is 11,460 years quondam.

Derivation of the Relationship Between One-half-Life Constants

Using the higher up equations, it is as well possible for a relationship to be derived between t_ane/2 , τ, and λ. This relationship enables the determination of all values, as long as at least 1 is known.