A certain radioactive isotope has a half-life of 25 years, which equates to a decay rate of 0.0278. If there are currently 200 grams of the isotope, determine how much of the isotope will remain after 10 years.(1 point) Responses There will be approximately 264.10 grams after 10 years. There will be approximately 264.10 grams after 10 years. There will be approximately 0.20 grams after 10 years. There will be approximately 0.20 grams after 10 years. There will be approximately 155.02 grams after 10 years. There will be approximately 155.02 grams after 10 years. There will be approximately 151.46 grams after 10 years.

1 answer

To determine how much of the radioactive isotope will remain after 10 years, we can use the decay formula:

\[ N(t) = N_0 e^{-kt} \]

where:

  • \(N(t)\) = remaining quantity of the substance after time \(t\),
  • \(N_0\) = initial quantity,
  • \(k\) = decay constant,
  • \(t\) = time in years.

In this case, we know:

  • \(N_0 = 200\) grams,
  • \(k = 0.0278\) (decay rate),
  • \(t = 10\) years.

First, we'll calculate \(N(10)\):

\[ N(10) = 200 e^{-0.0278 \cdot 10} \]

Calculating the exponent:

\[ -0.0278 \cdot 10 = -0.278 \]

Now, calculate \(e^{-0.278}\):

Using a calculator or a mathematical software to find \(e^{-0.278}\): \[ e^{-0.278} \approx 0.757 \]

Now, we can plug it back into the equation:

\[ N(10) \approx 200 \times 0.757 \]

Calculating this:

\[ N(10) \approx 151.46 \text{ grams} \]

Thus, the amount of the radioactive isotope that will remain after 10 years is approximately 151.46 grams.

Final Answer: There will be approximately 151.46 grams after 10 years.