The half- life of cobalt- 60 is 5.2 yr. How many milligrams of a 2.000- mg sample remains after 6.55 years?

Question

Quizplus · Accepted Answer

We can use the formula $N = N_0\left(\frac{1}{2}\right)^{\frac{t}{t_{1/2}}}$ where:
- $N_0$ is the initial amount of cobalt-60 (2.000 mg in this case)
- $N$ is the amount remaining after a certain amount of time
- $t$ is the elapsed time (6.55 years in this case)
- $t_{1/2}$ is the half-life of cobalt-60 (5.2 years in this case)

Plugging in the values, we get:
$N = 2.000\left(\frac{1}{2}\right)^{\frac{6.55}{5.2}} \approx 0.837$

Therefore, the amount remaining after 6.55 years is approximately 0.837 mg, which corresponds to choice C.

The Half- Life of Cobalt- 60 Is 5