Iodine-123 Is Used to Study Thyroid Gland Function

Iodine-123 is used to study thyroid gland function. This radioactive isotope breaks down in a first order process with a half-life of 13.1 hours. What is the rate constant, k , for the process?

A) k = 0.0529 hr ^{- 1}
B) k = 6.55 hr ^{- 1}
C) k = 9.08 hr ^{- 1}
D) k = 18.9 hr ^{- 1}
E) k = 26.2 hr ^{- 1}