Engineering Board Exam Reviewer · Environmental Engineering · hard
A pollutant decays by first-order kinetics with k = 0.2/ day. How long does it take for 90% of it to decay?
- 3.47 days
- 4.50 days
- 5.00 days
- 11.51 days
Answer
D. 11.51 days
Solution
C/C0 = 0.1 = e-kt t = 10/0.2 = 11.51 days.
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