Explore BrainMass

Explore BrainMass

    Calculation of Radioactive Disintegration Constant

    Not what you're looking for? Search our solutions OR ask your own Custom question.

    This content was COPIED from BrainMass.com - View the original, and get the already-completed solution here!

    A radio active substance has a half life of 30 days. Calculate
    (a) the radioactive disintegration constant (b) The average life
    (c) the time taken for ¾ of the original number of atoms to disintegrate and
    (d) the time taken for 1/8 of the original number of atoms to remain unchanged

    © BrainMass Inc. brainmass.com December 24, 2021, 4:46 pm ad1c9bdddf
    https://brainmass.com/physics/half-life/calculation-radioactive-disintegration-constant-6565

    SOLUTION This solution is FREE courtesy of BrainMass!

    Please see the attached document also.

    We have, T= 30 days
    (a) The radioactive disintegration constant λ = 0.693/T = 0.0231 per day (Ans)

    (b) Average life Ta = 1/λ = 1/0.0231 = 43.29 Days (Ans)

    (c) Number of atoms disintegrated ¾ N0 and the number of atoms left behind = ¼ N0
    N = N0 Exp (-λt)
    N/ N0 = Exp (-λt)

    But in this case, N/ N0 = ¼
    Or Exp (-λt) = ¼ λt = loge (4) = 2.3026 log10 (4)

    Substituting the value of λ,
    t = 2.3026 x 0.6021 / 0.0231 = 60 days (Ans)

    (d) In this case, N/ N0 = 1/8

    N/ N0 = Exp (-λt)

    Or, t = 2.3026 x log10 (8) / 0.0231
    = 90 days (Ans)

    Please see the attached document also.

    This content was COPIED from BrainMass.com - View the original, and get the already-completed solution here!

    © BrainMass Inc. brainmass.com December 24, 2021, 4:46 pm ad1c9bdddf>
    https://brainmass.com/physics/half-life/calculation-radioactive-disintegration-constant-6565

    Attachments

    ADVERTISEMENT