A freshly prepared sample of a certain radioactive isotope has an activity of 11.2 mCi. After 4.40 h, its activity is 8.00 mCi.
(a) Find the decay constant.
s-1
(b) Find the half-life.
h
(c) How many atoms of the isotope were contained in the freshly prepared sample?
(d) What is the sample's activity 30.2 h after it is prepared?
mCi