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Physics Class 12th Physics NCERT Exemplar Solutions Class 12th Chapter Thirteen Nuclei

The activity of a radioactive material is 2.56 × 10^-3 Ci. If the half life of the material is 5 days, after how many days the activity will become 2 × 10^-5 Ci?

Option 1 -

30 days

Option 2 -

35 days

Option 3 -

40 days

Option 4 -

25 days

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Answered by

Payal Gupta | Contributor-Level 10

3 months ago

Correct Option - 2

Detailed Solution:

A₀ = 2.56 * 10^-3C_i

A = 2 * 10^-15C_i

A = $\frac{A_{0}}{2^{n}}$

$\Rightarrow 2 \times 1 0^{- 5} = \frac{2.56 \times 1 0^{- 3}}{2^{n}}$

2ⁿ = 128

n = 7

t = 7 * t_1/2

= 7 * 5 = 35 days

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The activity of a radioactive material is 2.56 × 10^-3 Ci. If the half life of the material is 5 days, after how many days the activity will become 2 × 10^-5 Ci?

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The activity of a radioactive material is 2.56 × 10^-3 Ci. If the half life of the material is 5 days, after how many days the activity will become 2 × 10^-5 Ci?