Question

The half-life of a radioactive sample undergoing `alpha` - decay is 1.4 x 10¹⁷ s. If the number of nuclei in the sample is 2.0 x 10²¹, the activity of the sample is nearly ____________.

Options

• 10³ Bq

• 10⁴ Bq

• 10⁵ Bq

• 10⁶ Bq

Answer 1

The half-life of a radioactive sample undergoing `alpha` - decay is 1.4 x 10¹⁷ s. If the number of nuclei in the sample is 2.0 x 10²¹, the activity of the sample is nearly 10⁴ Bq.

Explanation:

Activity of the sample is given by,

`abs "R" = lambda "N"`

`abs "R" = 0.693/"T" xx "N"`

`abs "R" = 0.693/(1.4 xx 10^17) xx 2 xx 10^21`

`abs "R" = 9900 approx 10000`

` = 10^4  "Bq"`