1. Tardigrade
  2. Question
  3. Physics
  4. After 280 days, the activity of a radioactive sample is 6000 dps. The activity reduces to 3000 dps after another 140 days. The initial activity of the sample in dps is

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

 5927  167 IIT JEEIIT JEE 2004 Report Error

Solution:

Activity reduces from 6000 dps to 3000 dps 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 th of the initial activity. Hence, the initial activity of the sample is Therefore, the correct option is (d).