Thursday

November 27, 2014

November 27, 2014

Posted by **Sandhya** on Friday, April 18, 2008 at 9:16pm.

2) What is the activity of a sample of 14C that contains 1.22E+21 nuclei?

- physics-Radioactivity -
**Damon**, Saturday, April 19, 2008 at 4:53pm1) n(t) = No e^-kt

where n is number at t and No is starting number

when t = 15. n/No = 1/17 = .0588

so

.0588 = e^-15k

ln .0588 = -15 k

k = -2.833/-15 = .18888

so

what is t when n/No = 1/2 ??

.5 = e^-.18888 t

ln .5 = -.693 = -.18888 t

t = 3.67 days half life

- physics-Radioactivity -
**Sandhya**, Saturday, April 19, 2008 at 10:58pmThanks a lot Damon

Is my answer for the second problem correct?

- physics-Radioactivity -

**Answer this Question**

**Related Questions**

math - An unknown radioactive element decays into non-radioactive substances. In...

calc - The half-life of polonium is 139 days, but your sample will not be useful...

Calculus-Modeling Equations - An unknown radioactive element decays into non-...

Chemistry - A radioactive element has a half-life of 6.41 days. What percent of ...

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

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

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

Gen Chem - Neptunium-239 has a half-life of 2.35 days. How many days must elapse...

Chemistry - What is used to tell different isotopes of a particular element ...

Math/Calculus - After 5 days, a particular radioactive substance decays to 37% ...