# Learn How to Calculate the Radioactive Effective Half Life Time - Tutorial

## How to Calculate the Radioactive Effective Half Life Time - Definition, Formula and Example

##### Definition:

The process of bisecting the radioactive material in a living organism by utilizing 'radioactive decay and biological excretion' is known as effective half life. Decay or transformation constant existing in the radioactive decay is similar to the reciprocal value of half life. Time taken by an organism to reduce part of its radioactive element using biologic elimination and radioactive decay is the 'Effective half-life time' (m).

Here, (m) is equal to the product of the biologic half-life (bhl) and radioactive half-life (rhl) which is divided by the total of biologic half-life (bhl) and radioactive half-life (rhl).

#### Formula:

m = (bhl x rhl)/(bhl + rhl)
###### Where,

m = Effective half-life rhl = Physics half-life bhl = Biological half-life

##### Example:

The physical half-life time (rhl) of an living organism is 2 and the biological half-life (bhl) is 24 meters. Compute the effective half-life time (m) of an living organism?

##### Given,

Physical half-life [rhl]= 2 Biological half-life [bhl] = 24 meters Formula: m = (rhl x bhl) / (rhl + bhl) m = ( 2 x 24 ) / (2 + 24) m = 48/48 m = 1.846153846