The half life of a radioactive element is the time needed to the element to decay and reach the half amount of the initial amount. Here we have a radioisotope element which decays its half from 10,000 to 5,000 in two days. Therefore, its half life is 2 days.
<u><em>Q. 10g of white powder reacts with 10g of clear liquid. The reaction bubbles and changes color producing a black liquid that has a mass of 13g. What can be ...</em></u>