Hey there! Sign in to join this conversationNew here? Join for free
Turn on thread page Beta
    • Thread Starter
    Offline

    1
    ReputationRep:
    The question is to work out the age of the wooden tool. The tool has A carbon-14 activity of 0.07Bq per gram of total carbon content, half life of C-14 is 5700 years and carbon in the atmosphere has an activity of 19 disintegrations per minute.

    I worked this out to be 12400 years old but this seems far too old.
    I did this by using the equation t(1/2) = ln(A(0)/A)/(lambda); Where t(1/2) = half life = 5700 years, A(0) = initial activity = 0.316Bq = (19/60), A = activity = 0.07Bq and lambda = decay constant = ln(2)/t(1/2).

    Any help?
    Offline

    20
    ReputationRep:
    it says it is very old.... so why do you think your answer is wrong ?
    Offline

    20
    ReputationRep:
    (Original post by frostyfeet)
    The question is to work out the age of the wooden tool. The tool has A carbon-14 activity of 0.07Bq per gram of total carbon content, half life of C-14 is 5700 years and carbon in the atmosphere has an activity of 19 disintegrations per minute.

    I worked this out to be 12400 years old but this seems far too old.
    I did this by using the equation t(1/2) = ln(A(0)/A)/(lambda); Where t(1/2) = half life = 5700 years, A(0) = initial activity = 0.316Bq = (19/60), A = activity = 0.07Bq and lambda = decay constant = ln(2)/t(1/2).

    Any help?
    use this tool:

    https://www.math.upenn.edu/~deturck/.../carbdate.html

    to find the % C 14 figure * 0.07/0.316 *100 = 22.15%
    • Thread Starter
    Offline

    1
    ReputationRep:
    (Original post by the bear)
    it says it is very old.... so why do you think your answer is wrong ?
    I'm not sure, it just seems very old and I am not entirely sure if I have calculated initial activity correctly as it's phrased as 19 disintegrations per minute, not decay per second (although I did convert the time).
    • Thread Starter
    Offline

    1
    ReputationRep:
    (Original post by the bear)
    use this tool:

    https://www.math.upenn.edu/~deturck/.../carbdate.html

    to find the % C 14 figure * 0.07/0.316 *100 = 22.15%
    Thanks for this, it was really helpful.
    I checked my answer using this and it looks like it is right as long as I've got the initial activity correct.
 
 
 
Poll
“Yanny” or “Laurel”
Help with your A-levels

All the essentials

The adventure begins mug

Student life: what to expect

What it's really like going to uni

Rosette

Essay expert

Learn to write like a pro with our ultimate essay guide.

Uni match

Uni match

Our tool will help you find the perfect course for you

Study planner

Create a study plan

Get your head around what you need to do and when with the study planner tool.

Study planner

Resources by subject

Everything from mind maps to class notes.

Hands typing

Degrees without fees

Discover more about degree-level apprenticeships.

A student doing homework

Study tips from A* students

Students who got top grades in their A-levels share their secrets

Study help links and info

Can you help? Study help unanswered threadsRules and posting guidelines

Groups associated with this forum:

View associated groups

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Write a reply...
Reply
Hide
Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.