Question

Actinium-227 has a half-life of approximately 22 years. Which of the following equations correctly models the amount of actinium-227 remaining after t years? Round k to three decimal places.(1 point)

P
(
t
)
=
P
0
e
−
0.693
t


P
(
t
)
=
P
0
e
0.693
t


P
(
t
)
=
P
0
e
−
0.032
t


P
(
t
)
=
P
0
e
0.032
t

Answer 1

Use k = ln(1/2)/22 = -ln(2)/22 ≈ -0.693147/22 ≈ -0.0315 ≈ -0.032.

So the correct model is: P(t) = P0 e^(−0.032 t).