Cesium-134 is a β emitter with a half-life of 2.0 years. How much of a 2.50-g sample of cesium-134 will remain after 10 years?
A)0.0024 g
B)0.078 g
C)0.25 g
D)0.50 g
E)None of these choices are correct.

Question

Quizplus · Accepted Answer

We can use the radioactive decay formula to solve this problem:

N = N0 e^(-λt)

where N is the final amount, N0 is the initial amount, λ is the decay constant, and t is the time elapsed.

First, we need to find the decay constant from the half-life:

t1/2 = 2.0 years
λ = ln(2)/t1/2 = 0.693/2.0 = 0.3465 year^-1

Now we can plug in the values:

N = 2.50 g * e^(-0.3465 year^-1 * 10 years)
N = 0.078 g

Therefore, the answer is B) 0.078 g.

Cesium-134 Is a β Emitter with a Half-Life of 2