how carbon-14 is used to determine the age of an object

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gudden · Answer

Through Carbon Dating https://in.answers.yahoo.com/question/index?qid=20080227085919AAXX4eZ

koikkara · Answer

$\color{red}{~\star~"Welcome~to~Open~Study~!!"~\star~}$ $Carbon-14$ It is a Technique of determining the age of certain archeological artifacts of a biological origin up to about 50,000 years old. It is used in dating things such as bone, cloth, wood and plant fibers that were created in the relatively recent past by human activities. $For~Example:$ A child mummy is found high in the Andes and the archaeologist says the child lived more than 2,000 years ago. $How~??$ As soon as a living organism dies, it stops taking in new carbon. The ratio of carbon-12 to carbon-14 at the moment of death is the same as every other living thing, but the carbon-14 decays and is not replaced. The carbon-14 decays with its half-life of 5,700 years, while the amount of carbon-12 remains constant in the sample. By looking at the ratio of carbon-12 to carbon-14 in the sample and comparing it to the ratio in a living organism, it is possible to determine the age of a formerly living thing fairly precisely. A formula to calculate how old a sample is by carbon-14 dating is: t = [ ln (Nf/No) / (-0.693) ] x t1/2 where ln is the natural logarithm, Nf/No is the percent of carbon-14 in the sample compared to the amount in living tissue, and t1/2 is the half-life of carbon-14 (5,700 years). So, if you had a fossil that had 10 percent carbon-14 compared to a living sample, then that fossil would be: t = [ ln (0.10) / (-0.693) ] x 5,700 years t = [ (-2.303) / (-0.693) ] x 5,700 years t = [ 3.323 ] x 5,700 years t = 18,940 years old Because the half-life of carbon-14 is 5,700 years, it is only reliable for dating objects up to about 60,000 years old. However, the principle of carbon-14 dating applies to other isotopes as well. 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 use of various radioisotopes allows the dating of biological and geological samples with a high degree of accuracy. 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. $Half~Life~Of~Carbon~14$ Half life means the time it takes for half the sample to decay. For example, a half life of 20 years means that in 20 years half the sample will be gone. In another 20 years, half of that half will be gone, and so on, until there is nothing left. Also, Carbon 14 isn't usually used for dating fossils. It's half life is much too short for that. Other radiometric techniques are used, that have much longer half lives. $"Ref:~ http://www.chemteam.info/Radioactivity/WS-Half-life-C14only.html $ $Does~it~helps~??$ Don't Forget, $Appreciate~the~Best~Answer$ with a click on $\color{purple}{"Best Response"}$ Button Too ! @zhaneb. $\color{darkgreen}{~''Nice~To~Meet~You~!!"}$