Sunday

March 1, 2015

March 1, 2015

Posted by **barb** on Tuesday, April 10, 2007 at 11:46pm.

radioactive nuclei present on the day the sample arrives has disintegrated. For about how many days

after the sample arrives will you be able to use the polonium?

you want to know when you have 5% left.

Let P = c(2)^(-t/13), where c is the amount you started with, and t is the number of days.

so we want .05c=c(2)^(-t/139)

I used logs to solve and got t = 600 days

- calc -
**Billie**, Tuesday, February 9, 2010 at 4:19pmt=139ln(.05)/(ln(1/2))

t=139ln(.05)/(ln(1)-ln(2))

t=139ln(.05)/(0-ln(2))

t=139ln(.05)/(-ln(2))=600.7480052=600 days

t=(half life* ln(percent of sample left))/(ln(1/2))

**Answer this Question**

**Related Questions**

physics-Radioactivity - 1) The number of radioactive nuclei in a particular ...

Science math - Suppose a laboratory has a 38 g sample of polonium-210. The half-...

sciencemath - Suppose a laboratory has a 31 g sample of polonium-210. The half-...

science - Suppose a laboratory has a 31 g sample of polonium-210. The half-life ...

physics - Suppose 32000 radioactive nuclei are in a sample. About how many ...

Pre-Calc - A radioactive isotope has a half life of 8.1 days. If the sample ...

physics - Radioactive nuclei are produced in an irradiated sample at the rate of...

physics - The half life of a radioactive sample is 6.93 days.after how many days...

Chemistry - How many half lives will it take for a sample of a radioactive ...

SCIENCE - We did a radioactive decay and half life lab with m&ms and I do not ...