Thorium-229 is the radioactive substance that gives lantern mantels their eerie glow. The half life of thorium-229 is 7340 years.

If one mantel consists of 0.25 grams of thorium, how much thorium will remain after 14,680 years?

A) 0.0625g

B) 0.125g

C) 0.25g

D) 1.0g

Question

Physics

Karli Reed

8 July, 14:39

Thorium-229 is the radioactive substance that gives lantern mantels their eerie glow. The half life of thorium-229 is 7340 years.

If one mantel consists of 0.25 grams of thorium, how much thorium will remain after 14,680 years?

A) 0.0625g

B) 0.125g

C) 0.25g

D) 1.0g

+1

Answers (2)

Know the Answer?

Lana Escobar · Answer 1

Because 14,680 years is twice the half-life of thorium 229, two half lives would have elapsed during this time. If two half-lives pass, the amount of the sample would be cut in half twice. Half of 0.25g is 0.125g and half of this is 0.0625g.

A) 0.0625g

Draven Hopkins · Answer 2

0.0625 g would be left after that long!

Grams = 0.25 (0.5) ^ (14680/7340)

Grams = 0.0625

Thorium-229 is the radioactive substance that gives lantern mantels their eerie glow. The half life of thorium-229 is 7340 years.If one mantel consists of 0.25 grams of thorium, how much thorium will remain after 14,680 years?A) 0.0625gB) 0.125gC) 0.25gD) 1.0g

Thorium-229 is the radioactive substance that gives lantern mantels their eerie glow. The half life of thorium-229 is 7340 years.

If one mantel consists of 0.25 grams of thorium, how much thorium will remain after 14,680 years?

A) 0.0625g

B) 0.125g

C) 0.25g

D) 1.0g