The half-life of a radioactive sample is 5 seconds. If the initial mass of the sample is 60 grams then the time required to reduce the sample to 7.5 grams is:

Question

The half-life of a radioactive sample is 5 seconds. If the initial mass of the sample is 60 grams then the time required to reduce the sample to 7.5 grams is: (A) 15 secs (B) 75 secs (C) 7.5 secs (D) 10 secs

Tardigrade Admin · Accepted Answer

Decay scheme of given sample is as shown below <img class="img-fluid question-image" alt="image" src="https://cdn.tardigrade.in/img/question/physics/a861ad39fc51b4fe843405fb87e9a55b-.png" /> So, time required by sample to reduced to 7.5 g is Δ t=3 × T1 / 2=3 × 5=15 s

Q. The half-life of a radioactive sample is $5$ seconds. If the initial mass of the sample is $60$ grams then the time required to reduce the sample to $7.5$ grams is:

15 secs

75 secs

7.5 secs

10 secs

Decay scheme of given sample is as shown below

So, time required by sample to reduced to $7.5 g$ is
$Δ t = 3 \times T_{1/2} = 3 \times 5 = 15 s$

Q. The half-life of a radioactive sample is 5 seconds. If the initial mass of the sample is 60 grams then the time required to reduce the sample to 7.5 grams is: