# What is the time it takes for 50 percent of the nuclei in a radioactive sample to decay to its stable isotope called?

##### 1 Answer

Feb 20, 2017

#### Answer:

The half life.

#### Explanation:

After 1 half life 50 % of the substance is left.

After 2 half lives 25 %.

After 3 half lives 12.5 %.

After 4 half lives 6.25 %.

After 5 half lives 3.125 %.