Tritium is a radioactive isotope of hydrogen that decays by about 5% every year. A large bottle of water that contained 450,000 tritium atoms remained undisturbed for 11 years. How much tritium does the bottle contain now?

1 answer

To calculate the amount of tritium remaining after 11 years, we can use the formula:

N = N0 * (1 - r)^t

Where:
N = final amount of tritium after t years
N0 = initial amount of tritium
r = decay rate per year (5% = 0.05)
t = number of years

Plugging in the values:
N = 450,000 * (1 - 0.05)^11
N = 450,000 * (0.95)^11
N = 450,000 * 0.3138
N = 141,210

Therefore, after 11 years, the bottle contains approximately 141,210 tritium atoms.