# Transient Equilibrium Equation, Example

## Activity of Transient Equilibrium

##### Definition:

Equilibrium is a condition, where the state of two forces remains in a even state. In Nuclear Physics, transient equilibrium is a situation where both the parent and daughter attains the balanced condition. This concept is utilized to prove that the half life of the daughter is shorter than the half life of the parent. Normally, the transient equilibrium occurs at the end of four half life.

#### Formula:

Ad = Ap Tp / (Tp - Td)
##### Example:

Generally, the transient equilibrium occurs after four half life of the daughter (Td). According to the Molybdenum 99/Tc99m generator, the half life of the parent (Tp) is 67 hours. The activity of the parent will always be one. Let us consider the parent activity (Ap) as 1. The half-life of the Parent Tp as 67 hours and the half-life of the daughter Td as 4 hours. Let us calculate the equilibrium activity of the daughter. Given values are, Parent Activity Ap = 1 Half-life of the Parent Tp = 67 hours Half-life of the Daughter Td = 4 hours Substitute the values using the formula, Ad = Ap Tp / (Tp - Td) Ad = 1 x 67 / (67 - 4) Ad = 67 / 63 Ad = 1.063 Equilibrium activity of daughter derived is = 1.063 hours

Learn how to calculate the Activity of Transient Equilibrium using this tutorial with definition, formula and example.