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Hiroshima Little Boy Atomic Bomb Physics Help

  1. Mar 14, 2012 #1
    Hiroshima "Little Boy" Atomic Bomb Physics Help

    I just wanted some feedback on a paper I just finished. Did I do everything correctly and does it make sense? It seems my data supports information I found online: "It contained 64 kg (140 lb) of uranium, of which less than a kilogram underwent nuclear fission, and of this mass only 0.6 g (0.021 oz) was transformed into a different type of energy (initially kinetic energy, then heat and light)." http://en.wikipedia.org/wiki/Little_Boy

    Hiroshima “Little Boy” Atomic Bomb


    64 Kg of Uranium-235 used in bomb

    6.3 x 10^13 Joules released (estimated) during explosion


    E = mc2

    Energy Efficiency:

    6.3 x 10^13 = m x (300,000,000)2

    m = 7 x 10^-4

    Only .1% of starting Uranium-235 is turned to energy thus,

    (7 x 10^-4) / (.001) = .7 Kg


    “Little Boy” contained 64 Kg of Uranium-235 but, only .7 Kg of the starting mass was involved in the explosion. Furthermore, no more than .1% of the .7 Kg is converted to energy during nuclear fission. As a result, 7 x 10^-4 Kg of Uranium-235 was changed into 6.3 x 10^13 Joules.
  2. jcsd
  3. Mar 16, 2012 #2
    Re: Hiroshima "Little Boy" Atomic Bomb Physics Help

    0.7 kg Uranium was changed into 6.3 x 10^13 Joules and 0.6993 kg of fission products
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