If the amount of radioactive iodine123 in a sample decreases

If the amount of radioactive iodine-123 in a sample decreases from 0.4 g to 0.1 g in 26.4 h, what is the half-life, in hours, of iodine-123? 6.60 h/half-life 13.2 h/half-life 26.4 h/half-life 39.6 h/half-life 52.8 h/half-life

Solution

Answer:=13.2 h/half-life

Initial =0.4 g

Final =0.1g

Time taken= 26.4 h

0.4g--->0.2---->0.1 = 2 half lives

Therefore one half life is= 26.5/2 =13.2 h/half-life