Tritium has a half life of 12.5 years against beta decay. What fraction of a sample of pure tritium will remain undecayed after 25 years?

Explanation

To find the fraction of a sample of pure tritium that remains undecayed after 25 years, we can use the concept of half-life. Here’s a step-by-step solution:

### Step 1: Understand the half-life
The half-life of tritium is given as 12.5 years. This means that every 12.5 years, half of the tritium sample will decay.

### Step 2: Determine the total time elapsed
We are asked to find the remaining fraction after 25 years.

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