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lisabon 2012 [21]
3 years ago
5

The half-life of a radioactive substance is the average amount of time it takes for half of its atoms to disintegrate. Suppose y

ou started with 200 grams of a substance with a half-life of 3 minutes. How many minutes have passed if 25 grams now remain? Explain your reasoning.
Mathematics
2 answers:
Mila [183]3 years ago
8 0

Answer:

It would take 9 minutes for 25 grams of the substance to remain.

Step-by-step explanation:

Radioactive substance degenerate to release particles and lot of energy. The time required for a radioactive substance to degenerate into half of its original size is termed half life. The substance continues the stages of degeneration with respect to the half life.

The given substance would have 3 stages of degeneration to achieve a mass of 25 grams with respect to the half life.

1st stage, it would degenerate to half of its original size;

          = \frac{200}{2}

          = 100 grams

This occurs in 3 minutes.

2nd stage, it would degenerate to half of its previous size;

        = \frac{100}{2}

       = 50 grams

This also occurs in 3 minutes.

3rd stage, it would degenerate to half of it previous size;

         = \frac{50}{2}

        = 25 grams

This also occurs in 3 minutes.

We stop here due to the restriction in the question for 25 grams.

So, the total time taken for the substance to reach a mass of 25 grams

       = 3 + 3 + 3

       = 9 minutes

It would take 9 minutes for 25 grams of the substance to remain.

monitta3 years ago
3 0
3 half-lives because 200/2=100 100/2=50 and 50/2=25 
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castortr0y [4]

Answer:

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Step-by-step explanation:

The track is circular so it means that after Patrick raced the entire track he is back at the starting point. In other words, every 440 meters he is back to the beginning.

So we would have that, if he races round the track twice, he would run 440(2) = 880 meters and he would be back at the starting point.

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2 years ago
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