# U235 Dating Calculator

## Calculates the dating in the past from the ratio of Uranium 235 in natural uranium.

 Current ratio of U235 in natural uranium is the same anywhere in the solar system.Because the half-life is different with U238 and U235, the higher the percentage of U235 so retroactively.
 ratio at the dating
U235
 %
 ratio at the present
U235
 % half-life byr(109)
U238
 % half-life byr
 6dgt10dgt14dgt18dgt22dgt26dgt30dgt34dgt38dgt42dgt46dgt50dgt
 The enrichment ratio of U235 to be used in a nuclear reactor is about 3%, it is the same as the existing ratio of U235 2 billion years ago.The presence of natural reactor was predicted and found for this reason.$(1)\ x=x_0(\frac{1}{2})^{\frac{\normal t}{T}},\hspace{40}T:\ half\ time\\(2)\ t=-\frac{ln(\frac{x235}{100-x235}\frac{x238_0}{x235_0})}{ln2}\frac{1}{(\frac{1}{T235}-\frac{1}{T238})}\\$

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