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3 years ago

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Tungsten, W-181, is a radioactive isotope with a half life of 121 days. If a medical lab purchases 24 kg of W-181, how much will

be left after 1 year? A) 24 kg B) 12 kg C) 6 kg D) 3 kg

2 answers:

Bas_tet [7]3 years ago

6 0

The correct answer of this question is : 3 Kg

EXPLANATION :

As per the question, the half life period of W-181 : $t_{1/2}=\ 121\ days$

The initial amount of the specimen $N_{o}=\ 24\ Kg$

We are asked to calculate the amount of specimen left after one year.

Hence, the total time t = one year = 365 days.

Hence, total number of half lives n = $\frac{t}{t_{1/2}}$

= $\frac{365}{121}$

= $3.01$

= 3.

Let the amount left after one year is N.

Hence, the rest amount of specimen is calculated as-

$\frac{N}{N_{0}} =\ (\frac{1}{2})^n$

$=\ (\frac{1}{2})^3$

$=\ \frac{1}{8}$

⇒ $N=\ N_{0}\times \frac{1}{8}$

$=\ \frac{24}{8}\ Kg$

$=\ 3\ Kg$ [ans][

lorasvet [3.4K]3 years ago

4 0

D) 3 kg
One year is approximately 3 half lives of W-181. The amount remaining would be 1/23 or 1/8. That is 3 kg of W-181.

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