Turn on thread page Beta

Physics Questions (Moved from Gen. Chat - THINK Campaign) watch

    • Thread Starter
    Offline

    0
    ReputationRep:
    II am stuck on a couple of questions on product design and physics and if there is anyone out there to lend me a hand then please by all means do
    there isnt anyone available in the academic part at present

    anyone have any suggestions?
    Offline

    4
    ReputationRep:
    Yes - put up a better, more explanatory title and put the thread in the appropriate subforum.
    Offline

    10
    ReputationRep:
    What are your physics questions?
    Offline

    0
    ReputationRep:
    (Original post by nicad)
    II am stuck on a couple of questions on product <a href="http://www.ntsearch.com/search.php?q=design&v=55">design </a> and physics and if there is anyone out there to lend me a hand then please by all means do
    there isnt anyone available in the academic part at present

    anyone have any suggestions?
    sup.... post the physics question here and i'll do my best .... or PM me
    • Thread Starter
    Offline

    0
    ReputationRep:
    blimey quick replies

    here is the physics question

    Living plants absorb carbon dioxide from the atmosphere, a small quantity of which contains 14
    C
    6
    The Beta Minus Activity A0 ( little 0 ) from a living plant remains constant but once the plant dies, the activity decays according to the expression

    A = AoE - lambda/t

    where A is the activity at time t.

    Calculate

    i) the decay constant for Lamba for Carbon ( 14c6 )

    ii) the quantity f = the activity after 40,000 years
    ----------------------------
    the intial activity Ao

    iii) For objects over 40,000 years old, the carbon 14 beta minus emission becomes indistiguishable fom the background count. Explain the implications of this statement, making clear meaning of the term background count
    Offline

    0
    ReputationRep:
    (Original post by nicad)
    blimey quick replies

    here is the physics question

    Living plants absorb carbon dioxide from the atmosphere, a small quantity of which contains 14
    C
    6
    The Beta Minus Activity A0 ( little 0 ) from a living plant remains constant but once the plant dies, the activity decays according to the expression

    A = AoE - lambda/t

    where A is the activity at <a href="http://www.ntsearch.com/search.php?q=time&v=55">time</a> t.

    Calculate

    i) the decay constant for Lamba for Carbon ( 14c6 )

    ii) the quantity f = the activity after 40,000 years
    ----------------------------
    the intial activity Ao

    iii) For objects over 40,000 years old, the carbon 14 beta minus emission becomes indistiguishable fom the background count. Explain the implications of this statement, making clear meaning of the term background count
    hi hold on gota get calcy

    k

    for part i) um id have used Labda X T = 0.693

    then lambda = 0.693/5700 = 1.2 x 10-4

    ii ) take half lives: 40,000 / 5700 = 7.02 T giving 1 / 128 = 7.8 X 10 -3

    d) the background count is jst the random radioactivity, or count detected from the surroundings
    and the countrate is so low that no pattern of decay can be seen
    Offline

    0
    ReputationRep:
    anyone feel free to check but i'm pretty sure im right cuz ive been reading up on the stuff in detail about radioactivity for the unifying concepts
 
 
 

University open days

  1. Loughborough University
    General Open Day Undergraduate
    Fri, 21 Sep '18
  2. University of Cambridge
    Churchill College Undergraduate
    Fri, 21 Sep '18
  3. Richmond, The American International University in London
    Undergraduate Open Day Undergraduate
    Fri, 21 Sep '18
Poll
Which accompaniment is best?

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.