Finding the Optimal Distance for Electron Tunneling in Gold

[LisaMG]

Homework Statement

The work function (energy needed to remove an electron) of gold is 5.1 eV. Two pieces of gold (at the same potential) are separated by a distance L.

For what value of L will the transmission probability for an electron to cross from one to the other be T≈ 10-3? Assume that G = 1 in the formula for the tunneling probability.

(a) L = 0.001 nm
(b) L = 0.02 nm
(c) L = 0.1 nm
(d) L = 0.3 nm
(e) L = 4 nm

Homework Equations

T= Ge^(-2KL)
K=sqrt(2m/h^2 * (U-E))

The Attempt at a Solution

I have my final tomorrow, this is a practice exam. I tried to solve for K using 5.1eV for (U-E) and then solve for L but I can't figure it out.

 

[mfb]

I tried to solve for K using 5.1eV for (U-E) and then solve for L but I can't figure it out.

The approach is good, so unless you show your work there is no way to tell what went wrong.