Tuesday

April 21, 2015

April 21, 2015

Posted by **Jillian** on Wednesday, August 22, 2012 at 9:28am.

The decay constant for the radioactive element cesium 137 is .023 when time is measured in years. Find its half-life.

- Calculuc -
**drwls**, Wednesday, August 22, 2012 at 9:33ame^(-0.023t) = 0.5

Take natural log of both sides.

-0.023 t = -0.6932

t = 30 years

- Calculuc -
**Reiny**, Wednesday, August 22, 2012 at 9:39amIf you are using the standard decay function equation

amount = initial amount e^-kt, where k = .023 then

.5 = e^ -.023t

-.023t = ln .5

t = ln .5/-.023 = 30.14 years

check: pick 500 grams

amount = 500 e^(-.023(30.14))

= 500 e^ -.69314..

= 250

YUP!!!

word problem - The half life of cesium-137 is 30 years. Suppose we have a 10-g ...

Chemistry please help! - A Cesium 137 sample has a measured radioactivity of 50 ...

chem - Cesium-137 has a half life of 30.0 years. If initially there are 8.0 kg ...

algebra - Suppose a sample of Cesium-137 with initial mass of 200 grams decays ...

Physic - A radioactive element x has half life of 30 days and will decay to ...

Physic - A radioactive element x has half life of 30 days and will decay to ...

Physic - A radioactive element x has half life of 30 days and will decay to ...

Math - D.E.Q. - The half-life of a radioactive isotope is the amount of time it ...

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

Math - A radioactive substance decays according to the formula Q(t) = Q0e−...