Physics, 01.12.2020 14:00 25jzaldivar

The half-lives for the radioactive decay of various elements are listed below. Parent Isotope

Daughter Isotope

Half Life (years)

Carbon-14

Nitrogen-14

5730

Uranium-235

Lead-207

710 million

Potassium-40

Argon-40

1.25 billion

a) Suppose you discovered a meteorite that contains a small amount of potassium-40 and its decay product argon-40. You determine that 1/8 of the original potassium-40 remains; the other 7/8 has decayed into argon-40. How old is the meteorite?

b) A piece of cloth was painted with organic dye 34380 years ago. What percentage of the original carbon-14 in the organic dye remains after all this time?

c) The oldest minerals found on Earth are zircons. One isotope used to measure their age is uranium-235. A single crystal contained 20 nanograms of uranium-235 when it first formed. How much uranium-235 does the crystal still contain if it formed 2.84 billion years ago?

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The half-lives for the radioactive decay of various elements are listed below. Parent Isotope