AP Physics 2 : Radioactive Nuclear Decay

Study concepts, example questions & explanations for AP Physics 2

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Example Questions

Example Question #411 : Ap Physics 2

If an unknown compound undergoes radioactive decay such that  decays in , what is the rate constant for this reaction?

Possible Answers:

Correct answer:

Explanation:

In this question, we're told that a radioactive compound is decaying, and we're asked to determine the rate constant for the process.

Because radioactive decay reactions are first-order, we can use the first-order reaction equation.

Rearranging this expression, we can isolate the rate constant term, , as follows.

Now, we can plug in the values that were given to us in the question stem to calculate the answer.

Example Question #412 : Ap Physics 2

If it takes a radioactive compound  for  of it to decay, what is this reaction's rate constant?

Possible Answers:

Correct answer:

Explanation:

In this question, we're told that a radioactive compound has decayed by a certain amount in a given amount of time. We're asked to find the rate constant.

First, we have to recognize that all radioactive decay reactions follow first-order kinetics. Hence, we can use the first-order rate equation to solve this question.

Because we're told that  of the compound has decayed, we know there must be  of it left at the  mark.

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