Question

Is iodine-131 a radioactive material that decays according to the function a(t), where a₀ is the initial amount present and a is the amount present at time t (in days)?

a. Yes, it undergoes radioactive decay.

b. No, it remains stable over time.

c. It decays according to the inverse square law.

d. The decay is linear with time.

Answer 1

Iodine-131 is a radioactive material that decays in an exponential manner with a half-life of 8.02 days. The decay follows a first-order kinetic model, not linear, and the decay constant is 0.138 d⁻¹, which helps estimate the decay over time.

Step-by-step explanation:

Iodine-131 is indeed a radioactive material that decays over time. The correct answer to whether Iodine-131 decays according to the function a(t) is a. Yes, it undergoes radioactive decay. Iodine-131 exhibits first-order radioactive decay, characterized by an exponential decrease in the amount remaining over time, not a linear or inverse square law decay. The half-life of Iodine-131 is 8.02 days, which means that every 8.02 days, the amount of Iodine-131 will reduce to half its previous amount.

The decay constant for Iodine-131 is 0.138 d⁻¹, which can be used to estimate the time it will take for a certain percentage of Iodine-131 to decay. For instance, to calculate how many days it will take for 90% of Iodine-131 to decay, you can use the decay constant in a first-order decay equation.