Question 2.2 (6 marks) Radioactive materials, such as Plutonium-239, Radium-226, and others, decay exponentially. The amount of radioactive material present at time t can be described by R(t) = Rockt where t represents time (in years), and R(t) represents the amount of radioactive material present at time t. After 700 years, a sample of Plutonium-239 has decayed to 40% of its original mass. Find the half-life of this sample of Plutonium-239, i.e., the amount of time it takes for Plutonium-239 to decay to half it original mass