An isotope of a radioactive element has decay constant equal to 0.06 per year. Initially, there are 3 million atoms of the isotope present. Since the isotope decays exponentially, the number of atoms obeys the following equation P=3e^-0.06t In this question, time is measured in years and the number of atoms, P, is measured in millions. What is the value of the decay constant? Decay constant : ___ per year. What is the half-life of the isotope? (Enter your answer correct to two decimal places.) Half-life : ___years. How many million atoms will be present after 7 years have passed? (Enter your answer correct to one decimal place.) Number present after 7 years : ___ million.