The half life of oxygen-19 is only 29 seconds. Lets say we somehow instantly make a Liter of O-19 in a reactor. So at t = 0 we have 1 Liter of this isotope. What fraction of the O-19 isotope would be present after 5 seconds?
a. 88.5%
b. 83.2%
c. 79.9%
d. 77.37%