Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Particle in box - Getting confused by formula

  1. Aug 22, 2011 #1
    In my book of formulas I have a formula for energy in different states, particle in box. [itex]E_n = \frac{n^2 \pi^2 \hbar^2}{2ma^2}[/itex]

    So I should get Joule or something here right. A quick look at the formula.

    [itex]E_n = \frac{n^2 \pi^2 \hbar^2 [Js]}{2m[kg]a^2 [m^2]} \frac{ [Js]^2}{[kg]* [m^2]}[/itex] Becomes something like [itex]\frac{J s^2}{m^2}[/itex] After some rearrangement.

    What am I missing..?
  2. jcsd
  3. Aug 22, 2011 #2
    [tex]J= F[kg m/s^2]*d[m]=\frac{kgm^2}{s^2}[/tex]

    [tex]\implies [Js]^2= \frac{kg^2m^4}{s^2}\therefore \frac{[Js]^2}{kgm^2}=\frac{kgm^2}{s^2}=J[/tex]
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook