# Homework Help: Half life of lead 208

1. Jan 13, 2010

### 8614smith

1. The problem statement, all variables and given/known data
Calculate the half life for alpha decay of $$^{208}_{82}Pb$$ (in years)

2. Relevant equations
gamow factor
transmission probability
coloumb potential

3. The attempt at a solution
$$B=\frac{{Z_1}{Z_2}{e^2}}{4\pi{\epsilon_0}r}=\frac{80*2*(1.6x10^{-19})^{2}}{4*\pi*8.85*10^{-12}*8.896fm}=4.106*10^{-14}$$

where r = $$1.2(4^{1/3}+204^{1/3}) = 8.969fm$$

$$Q=[207.976635u-203.973476u-4.002603]c^{2}=8.30664*10^{-14}Joules$$

$$G=({2/137})({82-2}){\sqrt(\frac{2*4.0026*1.66*10^{-27}*9*10^{16}}{8.3066*10^{-14}}[{cos^{-1}}{\sqrt0.0202}-{\sqrt(0.0202)(1-0.0202)}]=11447.44$$

Is it supposed to be worked out in radians? because then the answer i get is 180.427 although this doesn't seem to give a right answer for the half life either

Is the gamow factor calculation correct?