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madam [21]
3 years ago
6

Please help me I need these extra credit points plz plz plz

Physics
2 answers:
KengaRu [80]3 years ago
6 0

Answer:

2 half lives have passed, the rock layer is 4,000 years old

Explanation:

It takes 2,000 years for half of the 400 atoms to decay which leaves you with 200 atoms. It then takes another 2,000 years for half of the 200 atoms to decay with leaves you with 100 atoms after a total of 4,000 years and 2 half lives.

VashaNatasha [74]3 years ago
5 0
Two half lives so it is 4000 years old
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