Problema Solution
The half life of a certaom substance is 29 years. How long will it take for a sample of this substance to decay 77% of its original amount? Use the exponential decay to solve.
Answer provided by our tutors
Half life of 29 years mean
0.5 = ek*29
ln 0.5 = 29k ln e
k = -0.0239
For 77% to decay:
(1-0.77) = e -0.0239*t
ln 0.23 = -0.0239 t ln e
t = 61.489 years