At time `t=0`, activity of a radioactive substance is 1600 Bq, at t=8 s activity remains 100 Bq. Find the activity at t=2 s.

Half-life of a radioactive substance is T. At time t_1 activity of a radioactive substance is R_1 and at time t_2 it is R_2 . Find the number of nuclei decayed in this interval of time.

Half-life of a radioactive substance is T. At time t_1 activity of a radioactive substance is R_1 and at time t_2 it is R_2 . Find the number of nuclei decayed in this interval of time.

At time t = 0 , number of nuclei of a radioactive substance is 100. At t = 1 s this number becomes 90. Find the number of nuclei at t = 2s.

At time t=0 , number of nuclei of a radioactive substance are 100. At t=1 s these numbers become 90. Find the number of nuclei at t=2 s .

At time t=0 , number of nuclei of a radioactive substance are 100. At t=1 s these numbers become 90 . Find the number of nuclei at t=2 s .

At time t=0 , number of nuclei of a radioactive substance are 100. At t=1 s these numbers become 90. Find the number of nuclei at t=2 s .