5 Puan Soru 3 In the formula A=lek, A is the amount of radioactive material remaining from an initial amount I at a given time t and k is a negative constant determined by the nature of the material. A certain radioactive isotope has a half-life of approximately 1,500 years. How many years would be required for a given amount of this isotope to decay to 60 % of that amount? A 600 yr B 1,045 yr 19 C 1,105 yr D 1,983 yr L