The activity of a radioactive isotope is `3000` count per minute at a certai time and `2736` count per minute after `48` h later. The half-life of this isotope is

The activity of a radioactive sample is measured as 9750 counts per minute at t = 0 and as 975 counts per minute at t = 5 minutes. The decay constant is approximately

The activity of a radioactive sample is measured as 9750 counts per minute at t = 0 and as 975 counts per minute at t = 5 minutes. The decay constant is approximately

The activity of a radioactive sample is measures as N_0 counts per minute at t = 0 and N_0//e counts per minute at t = 5 min . The time (in minute) at which the activity reduces to half its value is.

The activity of a radioactive sample is measures as N_0 counts per minute at t = 0 and N_0//e counts per minute at t = 5 min . The time (in minute) at which the activity reduces to half its value is.

The activity of a radioactive sample is measures as N_0 counts per minute at t = 0 and N_0//e counts per minute at t = 5 min . The time (in minute) at which the activity reduces to half its value is.

The activity of a radioactive sample is measured as N_0 counts per minute at t=0 and N_0//e counts per minutes at t=5 minutes. The time (in minutes ) at which the activety reduces to half its value is :