A Radiologist Uses a Radioactive Isotope of Iodine,¹²³I,for Thyroid Scans

A radiologist uses a radioactive isotope of iodine,¹²³I,for thyroid scans.She receives a shipment of 15 mCi of this isotope at noon on Tuesday.The half-life of this isotope is 13.2 h.How much activity remains at noon on Thursday of the same week?

A) 12 mCi
B) 1.2 mCi
C) 2.4 mCi
D) 4.2 mCi
E) 24 mCi