Question

(25 points) The half-life of tritium is 12.32 years. After 2 half lives, how much of a 200 gram sample of tritium will be left?

A. 25 grams
B. 100 grams
C. 200 grams
D. 50 grams

Answer 1

Answer:

D (50 grams)

Explanation:

As one half life is the time taken for half of a radioactive sample to decay.

When one half-life has occurred - we are left with $\frac{1}{2}$ of 200g, which is 100g.

Now another half-life occurs, which then decays $\frac{1}{2}$ of our remaining amount, so our 100g of Tritium decays into 50g.