Author Question: An archaeologist finds the 14C in a sample of of material to be decaying at 107 counts per second. A ... (Read 150 times)

mpobi80 · **on:** Jul 29, 2018

An archaeologist finds the 14C in a sample of of material to be decaying at 107 counts per second. A modern 1.00-g sample of the same material decays at 151 counts per second. The half-life of 14C is 5730 y. How old is the sample?

A) 12,200 y
B) 8460 y
C) 25,100 y
D) 12,600 y

Question 2

An ancient rock is found to contain 40Ar gas, indicating that of the 40K in the rock has decayed since the rock solidified. Any argon would have boiled out of liquid rock. The half-life of 40K is 1.25 billion years. How long ago did the rock solidify?

A) 2.6 billion years
B) 0.50 billion years
C) 1.8 billion years
D) 0.30 billion years