If a rock contains an isotope with a half live of 600 million years, and 0.5 half lives have elapsed since the rock formed, how old is the rock in millions of years?
If 1.0 half life passed, it would be 600 million years. If 0.1 half life passed, it would be 60 million years. Since 0.5 half life has passed, it is 300 million years old.
To determine the age of the rock, we'll need to understand the concept of half-life. The half-life of an isotope is the time it takes for half of the original amount of the isotope to decay.
In this case, the rock contains an isotope with a half-life of 600 million years. This means that after every half-life, half of the isotope remaining will decay.
Now, if 0.5 half-lives have elapsed since the rock formed, it means that half of the isotope has decayed. So, only half of the original amount of the isotope is still present in the rock.
To calculate the age of the rock, we can multiply the half-life by the number of half-lives that have elapsed. In this case, since 0.5 half-lives have passed, we'll multiply 600 million years by 0.5.
600 million years * 0.5 = 300 million years
Therefore, the rock is approximately 300 million years old.