Question

In the radioactive decay of element it is found that the count rate reduce from 1024 to 128 in 3 minute. its half time will be

Answer 1

then its half life and mean life are respectively [IIT 1989; MNR 1990; MP PET 1995, 97, 99, .... substance due to radioactive decay reduces to 10 gm in 4 minutes, then in what time ...