# Question #bbfad

##### 1 Answer

After **49 years** you'll have

What you've essentially have to perform is a nuclear half-life calculation starting from the initial ratio of tritium to hydrogen atoms.

In tritium's case, the total number of atoms will be reduced to half *after every half-life*; this means that you'll have half of the number of tritium atoms after **12.3 years**, a quarter of the initial tritium atoms after **2 * 12.3 = 24.6 years**, and so on.

Since normal hydrogen is considered stable, i.e. it has a half-life that's bigger than the age of the universe (by a lot), the number of hydrogen atoms will remain the same.

You can use the nuclear half-life equation to see how many tritium atoms you'll have after **49 years**

**(1)**, where

**t** years;

So, plug your data into this equation and solve for

Rounded to 1 sig fig, the number of sig figs in