How long does the pipe have to be to ensure that there is only 10% of the pollutants left in the kerosene?This means that we need a pipe that is 10.3 feet long in order for the pollutants to be reduced to 10% of their starting amount.The idea behind radiocarbon dating is straightforward, but years of work were required to develop the technique to the point where accurate dates could be obtained.Research has been ongoing since the 1960s to determine what the proportion of in the atmosphere has been over the past fifty thousand years.
000$ years: $\displaystyle m(12000) = m_0 e^ = 10^e^ \approx 2.34 \times 10^$ I think you can now do the ,000$ year case (just change the value of $t$).
Potassium-40 is another radioactive element naturally found in your body and has a half-life of 1.3 billion years.
Other useful radioisotopes for radioactive dating include Uranium -235 (half-life = 704 million years), Uranium -238 (half-life = 4.5 billion years), Thorium-232 (half-life = 14 billion years) and Rubidium-87 (half-life = 49 billion years).
The resulting data, in the form of a calibration curve, is now used to convert a given measurement of radiocarbon in a sample into an estimate of the sample's calendar age.
Other corrections must be made to account for the proportion of throughout the biosphere (reservoir effects).