The sample of rock if it has 15.625 grams of uranium -235 to decay will be 3.52 billion years. Then the correct option is B.
What is a half-life?
A radioactive material's half-life is the amount of time needed for half of the nucleus of an atom to decompose.
The half-life of uranium -235 is 703.8 million years.
A sample of rock started with 500 grams of uranium -235.
500 grams - 250 grams ⇒ 703.8 million years
250 grams - 125 grams ⇒ 703.8 million years
125 grams - 62.5 grams ⇒ 703.8 million years
62.5 grams - 31.25 grams ⇒ 703.8 million years
31.25 grams - 15.625 grams ⇒ 703.8 million years
Then the total number of years will be
Total years = 703.8 + 703.8 + 703.8 + 703.8 + 703.8
Total years = 3519 million years
Total years = 3.519 billion years
Total years = 3.52 billion years
The sample of rock if it has 15.625 grams of uranium -235 to decay will be 3.52 billion years.
Then the correct option is B.
More about the half-life link is given below.
https://brainly.com/question/24710827
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