Radioactive lead 82 Pb 201 has a half-life of 8 hours. Starting from one milligram of this isotope, how much will remain after 24 hours?

Question

Radioactive lead 82 Pb 201 has a half-life of 8 hours. Starting from one milligram of this isotope, how much will remain after 24 hours? (A)  (1/2)mg  (B)  (1/4)mg  (C)  (1/8)mg  (D)  (1/6)mg

Tardigrade Admin · Accepted Answer

We know that mass left = initial mass (1/2)× number of half lives Here, initial mass = 1 mg, number of half lives =(24/8)=3 ∴ mass left =1× ( (1/2) )3=(1/8)mg

Q. Radioactive lead, si^207 has a half life of 8 hours. Starting from 1 mg of $_{82} P b^{207}$ how much will remain after 24 hours?

$\frac{1}{2} m g$

$\frac{1}{4} m g$

$\frac{1}{8} m g$

$\frac{1}{6} m g$

We know that mass left = initial mass $\frac{1}{2} \times$ number of half lives Here, initial mass = 1 mg, number of half lives
$= \frac{24}{8} = 3$
$∴$ mass left $= 1 \times (\frac{1}{2})^{3} = \frac{1}{8} m g$

Q. Radioactive lead, si^207 has a half life of 8 hours. Starting from 1 mg of 82​Pb207 how much will remain after 24 hours?

21​mg

41​mg

81​mg

61​mg