Question

ReviewI Constants The technique known as potassium-argon dating is used to date volcanic rock and ash, and thus establish dates for nearby fossils like this hominid skull.(Figure 1) The potassium isotope "0K has a 1.28-billion-year half-life and is naturally present at very low levels. Its most common decay mode is beta-minus decay into the stable isotope 40 Ca, but 10.9% of its decays are beta-plus which result in the creation of the stable isotope 40 Ar. The high temperatures in volcanoes drive argon out of solidifying rock and ash, so there is no argon in newly formed material. After the rock and ash have completely solidified, however, argon produced in the decay of 40 K is trapped, so 40 Ar builds up steadily over time. Fairly accurate dating of an object is therefore possible by measuring the ratio ot the number of atoms of d°Ar to toK in nearby volcanic rocks. Figure < 1of1

Answer 1

CI (Mi) (K. ) (부유) I43 19š4-127 + 9.1713 0.99539で 사 No = inih"aZ vaba 嚐7adio ochv.nuda. nim 在 1.28 billim 0693 t 1280 million year 95317