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Radioactive dating I
Term | Definition |
---|---|
Radioactive Decay | The natural breakdown of unstable atoms into more stable atom. |
Absolute Age | The actual age or date of an event or thing in years before the present. |
Half Life | The time required for half of the atoms in a given radioactive mass to decay. |
The half-life for any given radioactive element is always | the same |
What will affect the half life of a radioactive isotope | Nothing |
which radioactive element would a scientist most likely have used to date the age of a fossil that is 10,000 years old | Carbon -14 |
Why is carbon-14 not usually used to accurately date objects more than 50,000 years old? | Carbon -14 has a relatively short half life and not enough carbon 14 has decayed after 50,000 years |
The most reliable determinations of the age of the earth are obtained from studies of | the half-life of certain radioactive minerals |
radioactive element has a half life of 4.5 x 10 9th years? | Uranium- 238 |
Where do you find radioactive elements half lives on Earth Science reference table? | 1st page |
If a radioactive element is placed under 50 tons of pressure, its half life will | remain the same. |
Samples of plant pollen are preserved in sediment deposited by the last glacial ice sheet in best for determining the age of the samples | carbon -14 |
Carbon -14 | all living, organic things |
A whalebone that originally contained 200 grams of radioactive carbon-14 now contains 25 grams of carbon-14. How many carbon-14 half lives passed since this whale was alive | 4 |
A rock sample containing the radioactive isotope potassium-40 is calculated to be 1.3 x 10 to the 9th years. How much of the original potassium would be left in this rock sample? | 50% |
If a specimen of a given radioactive substance is reduced in size, it's half life | remains the same |
A bone sample contains only 1/2 of its original radioactive c14 content. How old is the bones sample? | 1 c14 half life |
a Sample of rock contained 100 grams of potassium 40 when it was formed. Today the rock contains 50 grams of potassium-40. What is the age of the rock? | 1.3X10 to the 9th years |
Which radioactive isotope disintegrates to lead (pb206)? | U238 |