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 use of various radioisotopes allows the dating of biological and geological samples with a high degree of accuracy.
Note that this result is in agreement with the plot in Figure 1. 2) Estimate time for Polonium Po-210 to get 0.1 of its initial amount in the sample. Naturally occurring radiocarbon is produced as a secondary effect of cosmic-ray bombardment of the upper atmosphere.
However, radioisotope dating may not work so well in the future.
Anything that dies after the 1940s, when Nuclear bombs, nuclear reactors and open-air nuclear tests started changing things, will be harder to date precisely.
This is why it is such a big concern when a nuclear submarine sinks... (By the way, you are mostly Carbon-12, which is not radioactive.
Eventually, the salt water will eat through the steel and release the Plutonium (which, as you know, is quite lethal.) They usually talk about either trying to raise the sub or encase it in concrete where it rests. That's why we are called "Carbon-based life forms." Man, I've really watched too much Star Trek.)Scientists use Carbon-14 to make a guess at how old some things are -- things that used to be alive like people, animals, wood and natural cloths. Anyway, they make an estimate of how much Carbon-14 would have been in the thing when it died...
Solution Since 40% of Carbon-14 is lost, 60% is remained, or 0.6 of its initial amount.