# Physics

posted by TITA

If a sample of a radioactive isotope has a half-life of 5 year(s), how much of the original sample will be left at the end of the second year?

How much will be left at the end of the third year of thr original sample?

How much will be left at the end of the fourth year of the original sample?

1. drwls

Fraction left at t = (1/2)^(t/T)
where T is the half life, which is 5 years in this case.

For the first question, solve
(1/2)^(2/5) = 75.8%

Repeat using the same formula for the other times t.

## Similar Questions

1. ### Physics

A certian radioactive isotope has a half-life of 1 hour. If you start with 1 gram of the material at noon, how much of the original isotope will the sample contain at 3 pm?
2. ### Chemistry *URGENT*

URGENT help! 3. A rock sample was dated using potassium-40, Neasyrenebt ubducated tgat 1/8 of the original parent isotope is left in the rock sample. How old is the rock?
3. ### Chemistry

Gallium65, a radioactive isotope of gallium, decays by first order-kinetics. The half-life of this isotope is 15.2 min. How long would it take for 7/8 of a sample of this isotope to decay?
4. ### calculus

The rate at which an amount of a radioactive substance decays is modeled by the differential equation dA/dt = kA, where A is the mass in grams, t is the time in years, and k is a constant. Answer the following. a) If a 100-gram sample …
5. ### physics

If a radioactive isotope has a half-life of 1 year, how much of the original sample will be left at the end of the 2nd year?
6. ### Science

if a radioactive isotope has a half-life of one year, how much of the original sample will be left at the end of the second year?
7. ### Science

if a radioactive isotope has a half-life of one year, how much of the original sample will be left at the end of the second year?
8. ### math

You have just isolated a new radioactive element. If you can determine its half-life, you will win the Nobel Prize in physics. You purify a sample of 2 grams. One of your colleagues steals half of it, and eight days later you find …
9. ### Chemistry

If a 100.0 gram sample of a radioactive isotope goes through three half-lives, how much of the original radioactive isotope will remain?
10. ### Physics

Consider a radioactive sample with a half-life of one week. How much of the original sample will be left at the end of the second week?

More Similar Questions