# Homework Help: Barrier Tunneling

1. Oct 23, 2005

### Kazza_765

I can't work out what I am doing wrong in this question. Anyways, here it is:
A 3.0 MeV proton is incident on a potential energy barrier of thickness 10fm and height 10 MeV. What is the transmission coefficient T.
And here is what I have tried:
$$T=e^(-2bL)$$
$$b=\sqrt{\frac{8\pi^2m(U_b-E)}{h^2}}$$
$$b=\sqrt{\frac{8\pi^2(1.673*10^-27)\frac{10*10^6 - 3*10^6}{1.602*10^-19}}{(6.626*10^-34)^2}}$$
$$b=3.626*10^33$$
This gives me a transmission coeffecient of approximately 0, and the answer given in the book is 9.02*10^-6. Your help on this is much appreciated.

2. Oct 23, 2005

### Kazza_765

Never mind, as soon as I posted it and saw my equation in front of me I worked it out. Silly mistake.