Call Now to Set Up Tutoring:

(888) 888-0446

AP Physics 2 : Radioactive Nuclear Decay

Study concepts, example questions & explanations for AP Physics 2

Create An Account

All AP Physics 2 Resources

6 Diagnostic Tests 149 Practice Tests Question of the Day Flashcards Learn by Concept

Example Questions

Example Question #381 : Ap Physics 2

A scientist is working with a new radioactive nuclei. A sample has an activity of 199 Bq . 8 minutes later, it has an activity of 9 Bq .

Determine the nuclear decay constant.

Possible Answers:

None of these

$\frac{2.22*10^{-3}}{s}=\lambda$

$\frac{5.55*10^{-3}}{s}=\lambda$

$\frac{3.77*10^{-3}}{s}=\lambda$

$\frac{6.45*10^{-3}}{s}=\lambda$

Correct answer:

$\frac{6.45*10^{-3}}{s}=\lambda$

Explanation:

Use the relationship:

$A=A_0e^{-\lambda t}$

Here, is the activity at a given time, A_0 is the initial activity, $\lambda$ is the radioactive decay constant, and is the time passed since the initial reading.

Rearrange the equation to solve for $\lambda$ .

$\frac{(-ln(\frac{A}{A_0}))}{t}=\lambda$

Convert minutes to seconds and plug in values.

$\frac{(-ln(\frac{9 Bq}{199 Bq}))}{480s}=\lambda$

$\frac{6.45*10^{-3}}{s}=\lambda$

Report an Error

Example Question #381 : Ap Physics 2

A scientist is working with a new radioactive nuclei. A sample has an activity of 199 Bq . 8 minutes later, it has an activity of 9 Bq .

Determine the activity 4 minutes after the initial reading.

Possible Answers:

None of these

A=88Bq

A=25Bq

A=42Bq

A=2Bq

Correct answer:

A=42Bq

Explanation:

Use the relationship:

$A=A_0e^{-\lambda t}$

Here, is the activity at a given time, A_0 is the initial activity, $\lambda$ is the radioactive decay constant, and is the time passed since the initial reading.

Rearranging the equation to solve for $\lambda$ .

$\frac{(-ln(\frac{A}{A_0}))}{t}=\lambda$

Convert minutes to seconds and plug in values.

$\frac{(-ln(\frac{9 Bq}{199 Bq}))}{480s}=\lambda$

$\frac{6.45*10^{-3}}{s}=\lambda$

Again, use the relationship:

$A=A_0e^{-\lambda t}$

Using the new , which is equal to 4min=240s

$A=199e^{-6.45*10^{-3} 240}$

A=42Bq

Report an Error

Example Question #381 : Ap Physics 2

A scientist is working with a new radioactive nuclei. A sample has an activity of 199 Bq . 8 minutes later, it has an activity of 9 Bq .

Determine the number of radioactive atoms at the time of the initial reading.

Possible Answers:

N=8.11*10^4

N=2.34*10^4

N=3.01*10^4

None of these

N=8.87*10^4

Correct answer:

N=3.01*10^4

Explanation:

Use the relationship:

$A=A_0e^{-\lambda t}$

Here, is the activity at a given time, A_0 is the initial activity, $\lambda$ is the radioactive decay constant, and is the time passed since the initial reading.

Rearrange the equation to solve for $\lambda$ .

$\frac{(-ln(\frac{A}{A_0}))}{t}=\lambda$

Convert minutes to seconds and plug in values.

$\frac{(-ln(\frac{9 Bq}{199 Bq}))}{480s}=\lambda$

$\frac{6.45*10^{-3}}{s}=\lambda$

It is then necessary to use the relationship:

$A= \lambda N$

Use the initial activity and the calculated decay constant:

$199= \frac{6.45*10^{-3}}{s} N$

N=3.01*10^4

Report an Error

Example Question #34 : Atomic And Nuclear Physics

A scientist runs a test on a radioactive sample and finds that it has an activity of 6.0*10^3 Bq . Three days later, she runs another test and finds the activity to be 2.9*10^3Bq .

Another sample is tested. It has an activity of 3.8*10^4Bq . Determine the number of radioactive nuclei in it.

Possible Answers:

$N=1.36*10^{10}$

$N=7.75*10^{10}$

$N=1.36*10^{23}$

None of these

$N=1.12*10^{10}$

Correct answer:

$N=1.36*10^{10}$

Explanation:

Use the relationship:

$A=A_0e^{-\lambda t}$

Where is the activity at a given time, A_0 is the initial activity, $\lambda$ is the radioactive decay constant and is the time passed since the initial reading.

Rearrange to solve for $\lambda$ .

$\frac{(-ln(\frac{A}{A_0}))}{t}=\lambda$

Convert days to seconds and plug in values.

$\frac{(-ln(\frac{2.9*10^3 Bq}{6.0*10^3 Bq}))}{2.6*10^5s}=\lambda$

$\frac{2.8*10^{-6}}{s}=\lambda$

It is then necessary to use the relationship:

$A= \lambda N$

Use the initial activity and the calculated decay constant:

$3.8*10^4= \frac{2.8*10^{-6}}{s} N$

$N=1.36*10^{10}$

Report an Error

Example Question #382 : Ap Physics 2

A scientist runs a test on a radioactive sample and finds that it has an activity of 6.0*10^3 Bq . Three days later, she runs another test and finds the activity to be 2.9*10^3Bq .

Determine the number of radioactive nuclei in the original sample.

Possible Answers:

N=9.61*10^9

N=2.14*10^9

N=3.88*10^9

None of these

N=1.44*10^9

Correct answer:

N=2.14*10^9

Explanation:

Use the relationship:

$A=A_0e^{-\lambda t}$

Where is the activity at a given time, A_0 is the initial activity, $\lambda$ is the radioactive decay constant and is the time passed since the initial reading.

Rearrange to solve for $\lambda$ .

$\frac{(-ln(\frac{A}{A_0}))}{t}=\lambda$

Convert days to seconds and plug in values.

$\frac{(-ln(\frac{2.9*10^3 Bq}{6.0*10^3 Bq}))}{2.6*10^5s}=\lambda$

$\frac{2.8*10^{-6}}{s}=\lambda$

It is then necessary to use the relationship:

$A= \lambda N$

Use the initial activity and the calculated decay constant:

$6.0*10^3= \frac{2.8*10^{-6}}{s} N$

N=2.14*10^9

Report an Error

Example Question #381 : Ap Physics 2

A scientist runs a test on a radioactive sample and finds that it has an activity of 6.0*10^3 Bq . Three days later, she runs another test and finds the activity to be 2.9*10^3Bq .

Determine the half-life.

Possible Answers:

$8.35*10^5s=t_{1/2}$

$3.34*10^5s=t_{1/2}$

None of these

$2.48*10^5s=t_{1/2}$

$7.85*10^5s=t_{1/2}$

Correct answer:

$2.48*10^5s=t_{1/2}$

Explanation:

Use the relationship:

$A=A_0e^{-\lambda t}$

Where is the activity at a given time, A_0 is the initial activity, $\lambda$ is the radioactive decay constant and is the time passed since the initial reading.

Rearrange to solve for $\lambda$ .

$\frac{(-ln(\frac{A}{A_0}))}{t}=\lambda$

Convert days to seconds and plug in values.

$\frac{(-ln(\frac{2.9*10^3 Bq}{6.0*10^3 Bq}))}{2.6*10^5s}=\lambda$

$\frac{2.8*10^{-6}}{s}=\lambda$

Use the relationship:

$\frac{ln(2))}{\lambda}=t_{1/2}$

Plugin the calculated value for $\lambda$ :

$\frac{ln(2))}{2.8*10^{-6}}=t_{1/2}$

$2.48*10^5s=t_{1/2}$

Report an Error

Example Question #51 : Quantum And Nuclear Physics

A scientist is working with a new radioactive nuclei. A sample has an activity of 199 Bq . 8 minutes later, it has an activity of 9 Bq .

Determine the half life.

Possible Answers:

$28s=t_{1/2}$

None of these

$1000s=t_{1/2}$

$107s=t_{1/2}$

$77s=t_{1/2}$

Correct answer:

$107s=t_{1/2}$

Explanation:

Use the relationship:

$A=A_0e^{-\lambda t}$

Here, is the activity at a given time, A_0 is the initial activity, $\lambda$ is the radioactive decay constant, and is the time passed since the initial reading.

Rearrange the equation to solve for $\lambda$ .

$\frac{(-ln(\frac{A}{A_0}))}{t}=\lambda$

Convert minutes to seconds and plug in values.

$\frac{(-ln(\frac{9 Bq}{199 Bq}))}{480s}=\lambda$

$\frac{6.45*10^{-3}}{s}=\lambda$

Use the relationship:

$\frac{ln(2))}{\lambda}=t_{1/2}$

Plug in the calculated value for $\lambda$

$\frac{ln(2))}{6.45*10^{-3}}=t_{1/2}$

$107s=t_{1/2}$

Report an Error

Example Question #38 : Atomic And Nuclear Physics

A scientist runs a test on a radioactive sample and finds that it has an activity of 6.0*10^3 Bq . Three days later, she runs another test and finds the activity to be 2.9*10^3Bq .

Determine the activity of the sample 12 hours after the original reading.

Possible Answers:

A=5316Bq

None of these

A=4014Bq

A=4449Bq

A=6706Bq

Correct answer:

A=5316Bq

Explanation:

Use the relationship:

$A=A_0e^{-\lambda t}$

Where is the activity at a given time, A_0 is the initial activity, $\lambda$ is the radioactive decay constant and is the time passed since the initial reading.

Rearrange to solve for $\lambda$ .

$\frac{(-ln(\frac{A}{A_0}))}{t}=\lambda$

Convert days to seconds and plug in values.

$\frac{(-ln(\frac{2.9*10^3 Bq}{6.0*10^3 Bq}))}{2.6*10^5s}=\lambda$

$\frac{2.8*10^{-6}}{s}=\lambda$

Again, use the relationship:

$A=A_0e^{-\lambda t}$

Use the new , which is equal to 18min=1080s

$A=6.0*10^3e^{-2.8*10^{-6} 4.32*10^4}$

A=5316Bq

Report an Error

Example Question #21 : Radioactive Nuclear Decay

A particular radioactive sample initially has $20*10^{23}$ atoms and a half-life of 30min. How many atoms are there after 2hr?

Possible Answers:

$5.0 \times 10^{23}atoms$

$1.25 \times 10^{23}atoms$

$10.0 \times 10^{23}atoms$

$25.0 \times 10^{23}atoms$

$2.5 \times 10^{23}atoms$

Correct answer:

$1.25 \times 10^{23}atoms$

Explanation:

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:

$A_n=A_0\left(\frac{1}{2} \right )^n$

$A_n=20 * 10^{23}atoms\left(\frac{1}{2} \right )^4=1.25* 10^{23}atoms$

Report an Error

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 $4.28*10^{13} Bq$ . Three years later, the same sample has an activity of $8.78*10^{12} Bq$ .

Determine the decay constant of Banfordium.

Possible Answers:

$\frac{.711}{year}$

$\frac{.525}{year}$

$\frac{.825}{year}$

None of these

$\frac{.448}{year}$

Correct answer:

$\frac{.525}{year}$

Explanation:

Calculate the decay constant:

$A=A_0e^{-\lambda t}$

Solve for $\lambda$

$\lambda=-ln{\frac{A}{A_0}}*\frac{1}{t}$

Plug in values:

$\lambda=-ln{\frac{8.7*10^{12}}{4.2*10^{13}}}*\frac{1}{3}$

$\lambda=\frac{.525}{year}$

Report an Error

View Tutors

Hannah
Certified Tutor

Georgia State University, Master of Science, Social Work.

View Tutors

Richard
Certified Tutor

CUNY Brooklyn College, Bachelor of Science, Chemistry. CUNY Brooklyn College, Master of Arts, Experimental Psychology.

View Tutors

Traci
Certified Tutor

California State University-Fullerton, Bachelor of Science, History. UNLV, Masters in Education, Early Childhood Education.

All AP Physics 2 Resources

6 Diagnostic Tests 149 Practice Tests Question of the Day Flashcards Learn by Concept

Popular Subjects

SSAT Tutors in Atlanta, Calculus Tutors in Houston, Spanish Tutors in Philadelphia, MCAT Tutors in Houston, Computer Science Tutors in Miami, Reading Tutors in Dallas Fort Worth, Physics Tutors in Los Angeles, Statistics Tutors in New York City, SAT Tutors in Washington DC, Physics Tutors in San Francisco-Bay Area

Popular Courses & Classes

MCAT Courses & Classes in Boston, Spanish Courses & Classes in San Francisco-Bay Area, MCAT Courses & Classes in Phoenix, SSAT Courses & Classes in Boston, GMAT Courses & Classes in Denver, MCAT Courses & Classes in Los Angeles, GRE Courses & Classes in Chicago, ISEE Courses & Classes in Chicago, MCAT Courses & Classes in Philadelphia, MCAT Courses & Classes in Dallas Fort Worth

Popular Test Prep

MCAT Test Prep in Phoenix, ISEE Test Prep in Boston, ACT Test Prep in Houston, MCAT Test Prep in Atlanta, ISEE Test Prep in New York City, ISEE Test Prep in Atlanta, ISEE Test Prep in Chicago, GRE Test Prep in Washington DC, SAT Test Prep in Boston, GRE Test Prep in Atlanta

DMCA Complaint

If you believe that content available by means of the Website (as defined in our Terms of Service) infringes one or more of your copyrights, please notify us by providing a written notice (“Infringement Notice”) containing the information described below to the designated agent listed below. If Varsity Tutors takes action in response to an Infringement Notice, it will make a good faith attempt to contact the party that made such content available by means of the most recent email address, if any, provided by such party to Varsity Tutors.

Your Infringement Notice may be forwarded to the party that made the content available or to third parties such as ChillingEffects.org.

Please be advised that you will be liable for damages (including costs and attorneys’ fees) if you materially misrepresent that a product or activity is infringing your copyrights. Thus, if you are not sure content located on or linked-to by the Website infringes your copyright, you should consider first contacting an attorney.

Please follow these steps to file a notice:

You must include the following:

A physical or electronic signature of the copyright owner or a person authorized to act on their behalf; An identification of the copyright claimed to have been infringed; A description of the nature and exact location of the content that you claim to infringe your copyright, in \ sufficient detail to permit Varsity Tutors to find and positively identify that content; for example we require a link to the specific question (not just the name of the question) that contains the content and a description of which specific portion of the question – an image, a link, the text, etc – your complaint refers to; Your name, address, telephone number and email address; and A statement by you: (a) that you believe in good faith that the use of the content that you claim to infringe your copyright is not authorized by law, or by the copyright owner or such owner’s agent; (b) that all of the information contained in your Infringement Notice is accurate, and (c) under penalty of perjury, that you are either the copyright owner or a person authorized to act on their behalf.

Send your complaint to our designated agent at:

Charles Cohn Varsity Tutors LLC
101 S. Hanley Rd, Suite 300
St. Louis, MO 63105

Or fill out the form below:

Do not fill in this field

Contact Information

* Full legal name

Company name

* Phone number

* Email address

Address

* Address1

Address2

* City

* State

* Zipcode

* Country

Complaint Details

* URL of copyrighted work (where your original material is located)

* Please describe the copyrighted work so that it may be easily identified

I am the owner, or an agent authorized to act on behalf of the owner of an exclusive right that is allegedly infringed.

I have a good faith belief that the use of the material in the manner complained of is not authorized by the copyright owner, its agent, or the law.

This notification is accurate.

I acknowledge that there may be adverse legal consequences for making false or bad faith allegations of copyright infringement by using this process.

* Signature (your digital signature is legally binding)

HIGH SCHOOL

GRADUATE SCHOOL

K-8

Search 50+ Tests

math tutoring

science tutoring

foreign languages

elementary tutoring

other

Search 350+ Subjects

AP Physics 2 : Radioactive Nuclear Decay

Study concepts, example questions & explanations for AP Physics 2

All AP Physics 2 Resources

Example Questions

Example Question #381 : Ap Physics 2

Example Question #381 : Ap Physics 2

Example Question #381 : Ap Physics 2

Example Question #34 : Atomic And Nuclear Physics

Example Question #382 : Ap Physics 2

Example Question #381 : Ap Physics 2

Example Question #51 : Quantum And Nuclear Physics

Example Question #38 : Atomic And Nuclear Physics

Example Question #21 : Radioactive Nuclear Decay

Example Question #392 : Ap Physics 2

All AP Physics 2 Resources

Report an issue with this question

DMCA Complaint

Contact Information

Address

Complaint Details

Email address:
Your name:
Feedback: