- #1
clm222
I was studying for (first year) physics class and was playing around with the Bohr Model of Hydrogen. I tried calculating the electric potential at the Bohr radius r =5.29e-11 m, where [itex] V = \frac{e}{4 \pi \epsilon_0 r} [/itex] (from the point-charge formula for electric potential) and I got 27.19 J/C, but I am confused because the ionization energy of Hydrogen is 13.6eV, and doesn't that mean that the electron must be sent through 13.6 volts of electric potential?
I tried to calculate the potential and kinetic energies of the electron, [itex] U = qV =-eV [/itex] and [itex] {F_c} = \frac{mv^2}{r} [/itex] and [itex] F = qE = \frac{qV}{r}=\frac{+eV}{r}[/itex]
Therefore [itex] \frac{mv^2}{r}=\frac{qV}{r} →\frac{1}{2}mv^2 = \frac{+eV}{2}[/itex]
[itex]K=-\frac{1}{2}U[/itex]
So then this would seem to suggest to me that the net energy of the electron is simply [itex]K+U=\frac{1}{2} U=\frac{qV}{2}=\frac{-eV}{2}[/itex]
Does this imply that the (work) ionization energy is simply [itex]W=-U=-(\frac{-eV}{2})=+e(13.6V)=+13.6eV[/itex]?
Because it makes sense to me (assuming my calculations are correct) when calculating the work that the energy of an electron would just be 13.6eV at the Bohr radius, but doesn't make sense to me when it just passed through 27.19 volts of electric potential. Can someone please explain this to me?
Thanks a lot!
I tried to calculate the potential and kinetic energies of the electron, [itex] U = qV =-eV [/itex] and [itex] {F_c} = \frac{mv^2}{r} [/itex] and [itex] F = qE = \frac{qV}{r}=\frac{+eV}{r}[/itex]
Therefore [itex] \frac{mv^2}{r}=\frac{qV}{r} →\frac{1}{2}mv^2 = \frac{+eV}{2}[/itex]
[itex]K=-\frac{1}{2}U[/itex]
So then this would seem to suggest to me that the net energy of the electron is simply [itex]K+U=\frac{1}{2} U=\frac{qV}{2}=\frac{-eV}{2}[/itex]
Does this imply that the (work) ionization energy is simply [itex]W=-U=-(\frac{-eV}{2})=+e(13.6V)=+13.6eV[/itex]?
Because it makes sense to me (assuming my calculations are correct) when calculating the work that the energy of an electron would just be 13.6eV at the Bohr radius, but doesn't make sense to me when it just passed through 27.19 volts of electric potential. Can someone please explain this to me?
Thanks a lot!