If a nuclear medicine is found to be 1/32nd its original strength, how many half-lives have passed since the medicine was created in the laboratory?

5 half-lives

Explanation:

Original value Half-lives

1 0

1/2 1

1/4 2

1/8 3

1/16 4

1/32 5

This means it takes 5 half-lives after 1/32 of the original strength is found

Explanation:

Step 1: Data given

1/32 of the original strenght will remain after X time

Step 2: Calculate Number of half-life times

Let x be the number of half-lives.

For 1/32 left

2^-x = 1/32

x = 5

This means it takes 5 half-lives after 1/32 of the original sample is found

We can control this like:

After 1 half - life half of the sample is left = 1/2 of the original strength is found

After 2 half-lives, there will remain 1/4 of the original strength is found

After 3 half-lives, there will remain 1/8 of the original strength is found

After 4 half-lives, there will remain 1/16 of the original strength is found

After 5 half-lives, there will remain 1/32 of the original strength is found