Dating Fossils using Radioisotopes (p. 318)
1) a) 25%
2) around 35%
3) Specimen that are less than 10,000 years old cannot obtain accurate ages with the ratios between the argon and potassium. The decays into
4 a) C14, carbon 14 can be used.
b) Carbon 14 is useful from this isotope because once living organism face death, the intake of carbons are stopped. The carbon 14 decays with a short half-life of about 5,700 years (How stuff works, n.d.). As carbon 14 involves a shorter half-life, it may be more accurate in giving ages for the specimen than those of argon and potassium which have very long half lives. According to Wikipedia, the half life of 40K is 1.248(3)×109 years. This is very long compared to carbon 14.