Calculate the average life of a radioactive substance whose half-life period is 100 years.

Explanation

To calculate the average life of a radioactive substance given its half-life period, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Concept of Half-Life**:
- The half-life (t_half) of a radioactive substance is the time required for half of the radioactive nuclei in a sample to decay. In this case, the half-life is given as 100 years.

2. **Use the Formula for Average Life**:
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