A 1.0-Ci 137/55 Cs source is used for 2.0hourse by a 75-kg student in a physics lab.

Question:

A 1.0-μCi 137/55 Cs source is used for 2.0hourse by a 75-kg student in a physics lab. Radioactive 137/55Cs decays by β – decay with a half-life of 30 years. The average energy of the emitted betas is about 190keV per decay. The β decay is quickly followed by a y with an energy of 660keV. Assuming the student absorbs all emitted energy. What effective dose (in Rem) is received during lab?