Download 5.8 Exponential Growth and Decay

yes no Was this document useful for you?
   Thank you for your participation!

* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project

Document related concepts
no text concepts found
January 30, 2012
5.8 Exponential Growth and Decay
January 30, 2012
1. Iodine 131 is a radioactive material that decays according to the function
where A 0 is the initial amount present at time t (in days). Assume that a
scientist has a sample of 100 grams of iodine 131.
(a) What is the decay rate of iodine 131?
(b) How much iodine 131 is left after 9 days?
(c) When will 70 grams of iodine 131 be left?
(d) What is the half–life of iodine 131?
January 30, 2012
2. A culture of bacteria obeys the law of uninhibited growth.
(a) If N is the number of bacteria in the culture and t is the time in hours, express
(b) If 500 bacteria are present initially and there are 800 after one hour,
how many will be present in the culture after 5 hours?
(c) How long is it until there are 20,000 bacteria?