SOLUTION: The half-life of tritium is 12.4 years. How long will it take for 15% of a sample of tritium to decompose? An isotope of thorium, , has a half-life of 18.4 days. How long will

Question 198587: The half-life of tritium is 12.4 years. How long will it take for 15% of a sample of tritium to decompose?
An isotope of thorium, , has a half-life of 18.4 days. How long will it take for 77% of the sample to decompose?

Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
The half-life of tritium is 12.4 years. How long will it take for 15% of a sample of tritium to decompose?
If 15% decomposes, 85% remains.
-----------------
A(t) = Ao*e^(-ln(2t)/12.4)
0.85 = e^(-ln(2t)/12.4)
0.85 = 2t/12.4
2t = 10.54
t = 5.27 years

An isotope of thorium, , has a half-life of 18.4 days. How long will it take for 77% of the sample to decompose?
---
0.23 = e^(-ln(2t)/18.4)
0.23 = 2t/18.4
2t = 4.232
t = 2.116 days
=======================
Cheers,
Stan H.

RELATED QUESTIONS
The half-life of tritium is 12.4 years. How long will it take for 20% of a sample of... (answered by jim_thompson5910)

The half-life of a substance is the time it takes for half of the substance to remain... (answered by ankor@dixie-net.com)

An isotope of thorium, 227Th, has a half-life of 18.4 days. How long will it take for 85% (answered by jsmallt9)

Tritium (an isotope of hydrogen) has 2 neutrons. How many protons does it have? What is... (answered by solver91311)

The half life of a sodium is 15 hours. How long does it take for 95% of a sample of this (answered by ikleyn)

The Half-Life of radioactive isotope is the time it takes for quantity of the isotope to... (answered by josgarithmetic)

3. An isotope of sodium, Na^24, has a half-life of 15 hours. How many hours will it take... (answered by nerdybill)

The half-life of polonium-210 is 15 days. How long will it take for a sample of this... (answered by jorel1380)