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Homework Help: String length

  1. Jan 26, 2015 #1
    I am actually quite sure I have it right but my book would then be wrong so I have posted my problem here to see if I didn't do a embarassing mistake in arithmetics.
    1. The problem statement, all variables and given/known data
    "Show that the energy equivalent of the length 10-18cm of a large extra dimension is roughly 20TeV"
    -Zwiebach 2004

    2. Relevant equations

    mc2=ħc/ l
    3. The attempt at a solution
    Just some simple reforming first:


    then substituting numbers and converting units:


    E=200MeVx10-15 m / 10-16 m

    = 200 MeVx10x10

    =20000 MeV=2x1010 eV

    ,where Zwiebach says it schould be roughly 20 Tev 10^12 eV.

    Thanks for any clarifiactions
  2. jcsd
  3. Jan 26, 2015 #2


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    Is 0.01 cm = 1 m?
  4. Jan 26, 2015 #3
    I see.
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