
Concept explainers
In Exercises 6—10, we consider the phenomenon of radioactive decay which, from experimentation, we know behaves according to the law:
The rate at which a quantity of a radioactive isotope decays is proportional to the amount of the isotope present. The proportionality constant depends only on which radioactive isotope is used.
9. Engineers and scientists often measure the rate of decay of an exponentially decaying quantity using its time constant. The time constant
(a) How are the time constant
(b) Express the time constant in terms of the half-life.
(c) What are the time constants for Carbon 14 and Iodine 131?
(d) Given an exponentially decaying quantity r(t) with initial value r0= r(0), show that its time constant is the time at which the tangent line to the graph of r(t)/r0at (0, l) crosses the t-axis. [Hint: Start by sketching the graph of r(t)/r0and the line tangent to the graph at (0, 1).]
(e) It is often said that an exponentially decaying quantity reaches its steady state in five time constants, that is, at t =5

Want to see the full answer?
Check out a sample textbook solution
Chapter 1 Solutions
Differential Equations (with DE Tools Printed Access Card)
- Q4: Discuss the stability critical point of the ODES x + sin(x) = 0 and draw phase portrait.arrow_forwardUsing Karnaugh maps and Gray coding, reduce the following circuit represented as a table and write the final circuit in simplest form (first in terms of number of gates then in terms of fan-in of those gates). HINT: Pay closeattention to both the 1’s and the 0’s of the function.arrow_forwardRecall the RSA encryption/decryption system. The following questions are based on RSA. Suppose n (=15) is the product of the two prime numbers 3 and 5.1. Find an encryption key e for for the pair (e, n)2. Find a decryption key d for for the pair (d, n)3. Given the plaintext message x = 3, find the ciphertext y = x^(e) (where x^e is the message x encoded with encryption key e)4. Given the ciphertext message y (which you found in previous part), Show that the original message x = 3 can be recovered using (d, n)arrow_forward
- Algebra & Trigonometry with Analytic GeometryAlgebraISBN:9781133382119Author:SwokowskiPublisher:CengageAlgebra and Trigonometry (MindTap Course List)AlgebraISBN:9781305071742Author:James Stewart, Lothar Redlin, Saleem WatsonPublisher:Cengage Learning


