All AP Physics 2 Resources
Example Questions
Example Question #21 : Radioactive Nuclear Decay
A particular radioactive sample initially has atoms and a half-life of 30min. How many atoms are there after 2hr?
After 1 half-life of a radioactive sample has passed, only half of the initial particles will remain. We can see that 2 hours contains four 30-minute half-life periods. Therefore, through using our equation for radioactive decay:
Example Question #392 : Ap Physics 2
A new element is discovered named Banfordium. A test is run on a sample and finds it has an activity of . Three years later, the same sample has an activity of .
Determine the decay constant of Banfordium.
None of these
Calculate the decay constant:
Solve for
Plug in values:
Example Question #31 : Radioactive Nuclear Decay
A new element is discovered named Banfordium. A test is run on a sample and finds it has an activity of . Three years later, the same sample has an activity of .
Determine the half-life of Banfordium.
Calculate the decay constant:
Solve for
Plug in values:
Use the following relationship:
Plugging in values
Example Question #61 : Quantum And Nuclear Physics
A new element is discovered named Banfordium. A test is run on a sample and finds it has an activity of . Three years later, the same sample has an activity of .
Determine the number of Banfordium nuclei in a sample of activity
Calculate the decay constant:
Solve for
Plug in values
Convert to
Use the following relationship:
Plug in values and solve:
Example Question #41 : Atomic And Nuclear Physics
A new element is discovered named Banfordium. A test is run on a sample and finds it has an activity of . Three years later, the same sample has an activity of .
Determine the activity of the sample 10 years after the initial test.
Calculate the decay constant
Using
Solve for
Plug in values:
Use the following relationship:
Plug in values:
Example Question #62 : Quantum And Nuclear Physics
A sample of radioactive iodine is found to have decreased over time. After days, of radioactive iodine is found. Given that the half-life of radioactive iodine is days, how much radioactive iodine was there initially?
In this question, we're presented with a case in which a certain amount of radioactive iodine has decayed in a given amount of time. Based on the half-life, the amount of time that has passed, and the current amount of radioactive iodine, we're asked to solve for the initial amount of iodine.
First off, it's important to realize that this is a radioactive decay problem. All radioactive decay processes occur by a first-order reaction mechanism. Thus, we can go ahead and use the equation for first-order reactions:
Rearranging to isolate the term, we obtain:
But before we start plugging in values, we'll need to calculate the term, which is the reaction rate constant. We can do this because we know that the reaction is first-order, and we're also provided with the half-life. Using the rate constant equation for a first-order reaction:
Next, we can plug in the values given to us in order to solve for our answer:
Example Question #41 : Atomic And Nuclear Physics
The half life of is . Determine the radioactive decay constant.
Use the following formula:
Plug in values:
Example Question #41 : Atomic And Nuclear Physics
The half life of is . Determine the number of radioactive nuclei in a sample with an activity of .
Use the following formula:
Plug in values:
Covert to
Use the relationship:
Plug in values:
Example Question #41 : Atomic And Nuclear Physics
A sample is taken of a radioactive element. It has an activity of . Two hours later, it has an activity of .
Determine the nuclear decay constant in terms of .
None of these
Determination of decay constant:
Solving for
Converting hours to minutes and plugging in values:
Example Question #61 : Quantum And Nuclear Physics
A sample is taken of a radioactive element. It has an activity of . Two hours later, it has an activity of .
Determine the half life.
None of these
Determination of decay constant:
Solving for
Converting hours to minutes and plugging in values:
Using