Question -
Answer -
Half-life of┬аthe radioactiveisotope =┬аT┬аyears
Original amount of theradioactive isotope =┬аN0
(a)┬аAfterdecay, the amount of the radioactive isotope =┬аN
It is given that only 3.125%of┬аN0┬аremains after decay. Hence, we can write:
Where,
╬╗┬а= Decay constant
t┬а=Time
Hence, the isotope will takeabout 5T┬аyears to reduce to 3.125% of its original value.
(b)┬аAfterdecay, the amount of the radioactive isotope =┬аN
It is given that only 1% of┬аN0┬аremainsafter decay. Hence, we can write:
Since,┬а╬╗┬а=0.693/T
Hence, the isotope will takeabout┬а6.645T┬аyears to reduce to 1% of its original value.