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**Ideasman** I'm given $\displaystyle E_n = \frac{\hbar^2n^2\pi^2}{2ma}$ and I had to calculate $\displaystyle E_1$ which the book gets

$\displaystyle E_1 = 6\cdot 10^{-18}J = 37~eV$

No idea how... the orig. prob says that an electron has walls of width $\displaystyle 10^{-8}~ cm$ which I guess is our a. Then, we're given:

$\displaystyle \hbar = 6.58217\cdot 10^{-16}~ eV-s$

$\displaystyle m = 0.511~ MeV/c^2$

Guess c is light, which is: $\displaystyle 2.99792\cdot 10^{10}~ cm/s$.

So how exactly do they get that?