The ratio of the number of atoms of argon-40 to potassium-40 in a sample of radioactive rock is analysed to be 1: 3. Assume that there was no potassium in the rock originally and that argon-40 decays to potassium-40 with a half-life of 1500 million years. Assume there were N atoms of argon-40 in the rock when it was formed.
a) Calculate
i. the number of argon atoms left after 1500 million years
ii. the number of potassium atoms formed after 1500 million years
iii. the argon : potassium ratio after 1500 million years
iv. the number of argon atoms left after 3000 million years
v. the number of potassium atoms formed after 3000 million years
vi. the argon: potassium ratio after 3000 million years.
b. Estimate the age of the rock