# help

posted by .

the half-life of a radium is 1690 years is 90 grams is present now, how much will be present in 70 years

• physics -

(90 g)* 2^(-70/1690)
= 90g * 0.9717 = 87.5 g

## Similar Questions

2. ### Math - Exponential Decay

Radium decays exponentially. Its half-life is 1,690 years. How long will it take for a 50-gram sample of radium to be reduced to 5 grams?
3. ### Chemistry

Uranium-238 has half life of 4.51 * 10^9 years Uranium-234 has half life of 2.48 * 10^5 years Thorium-230 has half life of 8.0 * 10^4 years Radium-226 has half life of 1.62 * 10^3 years Lead-210 has half life of 20.4 years. The rate …
4. ### MATHS

experiments show that radium disintegrates at a rate proportional to the amount of radium present at the moment . if half life is 1590 years what percentage will disappear in one year?
5. ### MATHS

please help me ...Experiments show that radium at rate proportional to the amount of radium present at the moment . if half life is 1590 years what percentage will disappear in one year ?
6. ### Physics

(a)-A fossilised tree was tested and contains 10 grams of Carbon-14. Given that there was 12 grams of Carbon-14 present when it died, determine the age of the fossil?
7. ### Intermediate Maths

(a)-A fossilised tree was tested and contains 10 grams of Carbon-14. Given that there was 12 grams of Carbon-14 present when it died, determine the age of the fossil?
8. ### Final Maths

(a)-A fossilised tree was tested and contains 10 grams of Carbon-14. Given that there was 12 grams of Carbon-14 present when it died, determine the age of the fossil?
9. ### physics

the half life of radium is 1600 years of 100 grams of radium existing now 25 grams will remain after how many years
10. ### Physics

(a)-A fossilised tree was tested and contains 10 grams of Carbon-14. Given that there was 12 grams of Carbon-14 present when it died, determine the age of the fossil?

More Similar Questions