A solution of sodium iodide was given to a patient to test for malfunctioning of thyroid gland that containing iodine-131. Explain the fraction of the iodine-131 nuclei would remain un-decayed after9.0 d?
How many micrograms remain after 9.0 d? The half-life of I-131 is 8.07 d if a sample contains 2.8 µg of131I.