Chapter 4.2, Problem 9E

Reminder Round all answers to two decimal places unless otherwise indicated.

Unit Conversion with Exponential Decay The exponential function $N=500\times {0.68}^{\text{t}}$, where $t$ is measured in years, shows the amount, in grams, of a certain radioactive substance present.

a. Calculate $N\left(2\right)$ and explain what your answer means.

b. What is the yearly percentage decay rate?

c. What is the monthly decay factor rounded to three decimal places? What is the monthly percentage decay rate?

d. What is the percentage decay rate per second? (Note: For this calculation, you will need to use all the decimal places that your calculator can show.)