String length

  • Thread starter moriheru
  • Start date
  • #1
272
17
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.

Homework Statement


"Show that the energy equivalent of the length 10-18cm of a large extra dimension is roughly 20TeV"
-Zwiebach 2004

2. Homework Equations

ħ=c=1
ħc≈200MeVx10-15m
ls=√α
mc2=ħc/ l

The Attempt at a Solution


Just some simple reforming first:

E=mc2=ħc/l

then substituting numbers and converting units:

10-18cm=10-16m

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
 

Answers and Replies

  • #3
272
17
I see.
 

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