After 280 days, the activity of a radioactive sample is 6000 dps. The activity reduces to 3000dps after another 140 days. The initial activity of the sample(in $dps$) is

Question

Dr. Abubacker · Accepted Answer

(d) Activity reduces from 6000dps to 3000dps in 140 days. It implies that half-life of the radioactive sample is 140 days. In 280 days (or two half-lives)activity will remain $\frac{1}{4}$ th of the initial activity . Hence the initial activity of the sample is
4 $	imes$ 6000 dps = 24000 dps

Q. After 280 days, the activity of a radioactive sample is 6000 dps. The activity reduces to 3000dps after another 140 days. The initial activity of the sample(in $dps$) is

Explanation

Reviewed by Dr. Abubacker

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