Suppose You Find a Rock That Contains Some Potassium-40 (Half-Life

question 42

Multiple Choice

Suppose you find a rock that contains some potassium-40 (half-life of 1.3 billion years) .You measure the amount and determine that there are 5 grams of potassium-40 in the rock.By measuring the amount of its decay product (argon-40) present in the rock,you realize that there must have been 40 grams of potassium-40 when the rock solidified.How old is the rock?

• A)1.3 billion years
• B)2.6 billion years
• C)3.9 billion years
• D)5.2 billion years
• E)none of the above

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