AP Calculus AB: 11.2.3 Radioactive Decay
This content explains how radioactive decay follows exponential decay laws, using the same mathematical model as exponential growth but with a negative rate. It includes examples involving half-life calculations, solving for unknown quantities, and forming differential equations to describe decay processes.
Radioactive Decay
Radioactive substances decay over time. The time required to decay by half is called the half-life.
The same equations that govern exponential growth apply to radioactive decay.
Key Terms
Radioactive Decay
Radioactive substances decay over time. The time required to decay by half is called the half-life.
The same equations that ...
note
While exponential growth involves increases that are
proportional to the original amount, radioactive decay
involves decreases that a...
A radioactive material is known to decay at a yearly rate proportional to the amount at each moment. There were 1000 grams of the material 10 years ago. There are 980 grams right now. What was the amount of the material 30 years ago?
10^9/980^2
A radioactive material is known to decay at a yearly rate of 0.3 times the amount at each moment. Which of the following differential equations describes the rate of radioactive decay?
dP/dt=−0.3P
A radioactive material is known to decay at a yearly rate proportional to the amount at each moment. There are 2000 grams of the material right now. Its half-life is known to be 1600 years. What is the amount right after t years?
2000 ⋅ 2^−t / 1600
A radioactive material is known to decay at a yearly rate proportional to the amount at each moment. There were 1000 grams of the material 10 years ago. There are 980 grams right now. What will be the amount of the material right after 20 years?
980^3/10^6
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| Term | Definition |
|---|---|
Radioactive Decay |
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note |
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A radioactive material is known to decay at a yearly rate proportional to the amount at each moment. There were 1000 grams of the material 10 years ago. There are 980 grams right now. What was the amount of the material 30 years ago? | 10^9/980^2 |
A radioactive material is known to decay at a yearly rate of 0.3 times the amount at each moment. Which of the following differential equations describes the rate of radioactive decay? | dP/dt=−0.3P |
A radioactive material is known to decay at a yearly rate proportional to the amount at each moment. There are 2000 grams of the material right now. Its half-life is known to be 1600 years. What is the amount right after t years? | 2000 ⋅ 2^−t / 1600 |
A radioactive material is known to decay at a yearly rate proportional to the amount at each moment. There were 1000 grams of the material 10 years ago. There are 980 grams right now. What will be the amount of the material right after 20 years? | 980^3/10^6 |
A radioactive material is known to decay at a yearly rate of 0.3 times the amount at each moment. There are 1000 grams of the material right now. Which of the following equations describes the amount of material as a function of time? | P = 1000 e ^−0.3t |
A radioactive material is known to decay at a yearly rate proportional to the amount at each moment. There were 2000 grams of the material 10 years ago. There are 1990 grams right now. What is the half-life of the material? | 10 ln2/ln(2000/1990) |
A radioactive material is known to decay at a yearly rate of 0.04 times the amount at each moment. There are 2000 grams of the material right now. What is the amount (in grams) after 10 years? | 1.3×10^3 |
A radioactive material is known to decay at a yearly rate proportional to the amount at each moment. There are 1000 grams of the material right now. Its half-life is known to be 1500 years. What is the amount right after t years? | P(t)=1000e^−(ln2)t/1500 |