Question

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`.

Answer 1

Correct Answer - A
In 1 second, 90% of the nuclei have remained undecayed, so in another 1 second 90% of 90, i.e. 81 nuclei will remain undecayed.