SOLUTION: The half-life of iodine-131 is 7.2 days. How long will it take for a sample of this substance to decay to 30% of its original amount? Round to one decimal place.

Question 852103: The half-life of iodine-131 is 7.2 days. How long will it take for a sample of this substance to decay to 30% of its original amount? Round to one decimal place.
Answer by ewatrrr(24785) (Show Source): You can put this solution on YOUR website!

 

Hi,

  0r   

Finding 'k' first

 .5 = e^(-7.2k)

 = k = .0963

 .3 = e^(-.0963t)

 = t

  

RELATED QUESTIONS

The half-life of polonium-210 is 15 days. How long will it take for a sample of this... (answered by jorel1380)
Iodine-131 is a radioactive material used to treat a certain types of cancer. Iodine-131... (answered by ankor@dixie-net.com)
Iodine-131 is used to find leaks in water pipes. It has a half life of 8.14 days. Write... (answered by stanbon)
Use the exponential decay equation given below, where A is the amount of a radioactive... (answered by josgarithmetic)
The half-life of radioactive iodine 131 is approximately 8.3 days. 
a) Find an... (answered by josgarithmetic,Boreal)
8.	Radioactive materials like uranium follow the law of uninhibited decay, which is an... (answered by josgarithmetic)
The half life of radioactive element plutonium-239 is 20 years.
How long will it take... (answered by ankor@dixie-net.com)
The half-life of a certain substance is 27. How long will it take for a sample of this... (answered by josgarithmetic)