Make sure that you are showing each step of your work.
- The half-life of cobalt-60 is 5.27 years. How many milligrams of cobalt-60 remain after 52.7 years if you start with 15 mg?
- A sample contains 12.0 mg of an unknown element. After 4.46 × 109 years, the sample will contain 3.00 mg of the unknown element. What is the half-life of the unknown element?
“Make sure to show your work, and your answers should be provided with the correct amount of significant figures.”