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? O2.6 billion years 0.30 billion years O 1.8 billion years O 0.50 billion years

A fossil is found that contains 6.25% as much Radium-226 as fossils being formed today. The half-life of Radium -226 is 1.60 x103 years. How old is the fossil? Hint: How many half-lives did the Radium-226 go through for 6.25% to remain? So, how many years have passed over 4 half lives?

Uranium-lead (U-Pb) dating of geological samples is one of the oldest and most refined radiometric dating methods, able to determine ages of about 1 million years to over 4.5 billion years with precision in the 0.1–1% range. The U-Pb dating method relies on two separate decay chains, one of which is the actinium series from 235U to 207Pb, with a half-life of 704 million years.   Geologists unearth a sample of zircon that appears to be a closed system. They find 0.714  grams of 207Pb for 1.000 grams of 235U present. Approximately how old is the sample? _______ yrs

Each time you dumped the pennies, one half-life passed; it has been shown that thehalf-life for this radioactive isotope is 20 years. In the year 2000, an archaeology teamunearths pottery and is using this isotope for radiometric dating to place the age of thepottery. It is shown that 95% of the nuclei have decayed. Using your graph,approximately how long ago was the pottery made?

Determine the age of a certain rock sample: carbon -14 half life = 5730 years. An archeology dig unearths a skeleton. Analysis shows is a C-14 activity of 1Cpm per gram of total carbon. Approximately how old is the skeleton?(Original C-14 Activity= 16Cpm)

Using the differential equation model: (dN/dt) = -kN. (k>0) where N(t) = amount of 14C at time t, approximately how old is a fossil with 17 g of 14C if it initially possessed 45 g of ¹4c? (Note: assume half life of 14C to be 5700 years) Choose All Correct Answers Below (A) 7650 years B) 8005 years C) 5792 years D 9430 years 1012 years 9622 years

Approximately how old is a fossil that contains 1.5g of C14 and 198.5g of C12? Remember that C14 decays to C12 with a half life of 6,000 years.

A fossil is found to have a 14Clevel of 63.0% compared to living organisms. How old is the fossil?

What fraction of the 40K that was on Earth when it formed 4.5 X 109 years ago is left today?

Radimetric Dating Calculations:The half life of 40K is approximately 1.3 billion years, and it decays to 40Ar, which is trapped in igneous rocks as 40K decays.  If we find a sample of granite in which the ratio of 40Ar/40K is 3/1, then how old is the sample?