[填空题]
(a) A 92-gram sample of natural carbon chd98 wi l ufehqlr//mp cb :2j;a0(8svontains the usu n hte-w ftwl)4fl+:ud/f mn3*al fraction of $_{6}^{14}\text{C}$. Estimate how long it will take before there is only one $_{6}^{14}\text{C}$ nucleus left. t = $ \times 10^{5}\ \text{yr}$2.4
(b) How does the answer in (a) change if the sample is 280 grams? What does this tell you about the limits of carbon dating? $10^a$yr a =
