# Phosphorus-32 is radioactive and has a half life of 14.3 days. How long would it take a sample to decay from 2.20 mg to 600 #mu#g?

##### 1 Answer

Nov 1, 2016

#### Answer:

26.8 days.

#### Explanation:

The equation for 1st order decay is:

We can get the value of the decay constant

Taking natural logs of both sides:

Putting in the numbers and converting to milligrams: