1. PF Contest - Win "Conquering the Physics GRE" book! Click Here to Enter
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Radioactive decay. Is energy released? OPINION PLEASE

  1. May 1, 2008 #1
    [SOLVED] Radioactive decay. Is energy released? OPINION PLEASE!!!

    This is my last question in my last Physics exam!!!
    YES!!! I'M ALMOST DONE!!!! :rofl:

    I would just like your opinion on this question...
    My answer is Yes.... But sometimes I think it should be NO because
    of the question's option for a No answer. But from what I understand
    in the textbook, the answer should be YES.


    The decay of [tex]\frac{226}{88}[/tex]Ra results in the release of some energy. Your book tells you that energy
    is released in a nuclear reaction when mass is changed to energy. Yet there are the same
    number of nucleons before the decay as there are after the decay. Is energy released
    in this reaction without a conversion of mass? If not, what mass is converted?

    2. MY ANSWER:

    Yes, energy is released in this reaction even though the total amount of nucleons in the two new atoms are still the same. Why? Well, the textbook says that when an element transmutates, energy is released in three forms: gamma radiation, the kinetic energy of the alpha or beta particle, and the kinetic energy of the new element. In addition, gamma radiation is massless energy. So if the radium particle emitted gamma rays, its mass would not be affected, even though energy was released.

    FYI: This question is a continuation of the previous problem, which is: [tex]\frac{226}{88}[/tex]Ra decays into Rn (atomic #86) and an alpha particle. Complete the reaction written below.

    [tex]\frac{226}{88}[/tex]Ra [tex]\Rightarrow[/tex] (my answer follows) [tex]\frac{222}{86}[/tex]Rn + [tex]\frac{4}{2}[/tex]He
  2. jcsd
  3. May 1, 2008 #2
    If you add up the masses of the reaction products, you'll find that they are lighter. mass is converted to energy.
  4. May 1, 2008 #3


    User Avatar
    Science Advisor
    Homework Helper

    If energy isn't released then the Mayor of Hiroshima has some questions to answer about a very large insurance claim.
  5. May 18, 2008 #4
    lol :D
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook