19.5k views
4 votes
A meteorite is determined to be 4.5 billion years old. It now has 78 atoms of lead-206. Assuming no loss of daughter isotopes, how many atoms of uranium-238 did the meteorite have to begin with? The half-life of uranium-238 is 4.5 billion years.

a) 156
b) 312
c) 78
d) 238

User BorisTB
by
8.5k points

1 Answer

3 votes
Given the age of the meteorite is 4.5 billion years old with 78 atoms of lead-206 the answer should be B. 156. The half-life of uranium-238 in order to decay into lead-206 is 4.46 billion years, which means that the original number of atoms is 156.
User Long Nguyen Duc
by
7.4k points
Welcome to QAmmunity.org, where you can ask questions and receive answers from other members of our community.