The oldest meteorite found on earth to date is EC002. Scientists dated the meteorite using the decay of potasium 40(K 40 ) into argon 40(Ar40 ). Assuming that there were originally 2×10 ⁹ micrograms of K 40 when they found the meteorite 100 years ago and that there are now 1,999,999,893 micrograms, what is the half-life of K 40 ? Use A=P( 21​ ) t/k , where k is the half-life and t is in years. (b) The scientists estimate that the amount of K 40 at the time of impact was 2.34×10 ¹⁰ micrograms. How old is EC002? Now, look up the age of the earth. (c) When were there 4×10 ⁹ micrograms of K 40 ? You don't need a calculator for this part! (d) Redo part a using A=Pe ʳᵗ . What is the relationship between r and k ?