If You Obtained a Sample of Rock from Venus and Determined

question 51

Multiple Choice

If you obtained a sample of rock from Venus and determined the abundances of uranium (²³⁸U) and lead (²⁰⁷Pb) in it, and found that for every one uranium atom there were three lead atoms, then what would the age of this rock be? Note that this form of uranium decays to this form of lead with a half-life of 700 million years. For simplicity, you can assume that there was no lead in the rock when it originally formed.

• A) 1.4 billion years
• B) 2.8 billion years
• C) 4.0 million years
• D) 10.5 billion years
• E) 3.6 billion years

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