Answer:
3.1% is the fraction of the sample after 28650 years
Step-by-step explanation:
The isotope decay follows the equation:
Ln[A] = -kt + Ln[A]₀
Where [A] could be taken as fraction of isotope after time t, k is decay constant and [A]₀ is initial fraction of the isotope = 1
k could be obtained from Half-Life as follows:
K = Ln 2 / Half-life
K = ln 2 / 5730 years
K = 1.2097x10⁻⁴ years⁻¹
Replacing in isotope decay equation:
Ln[A] = -1.2097x10⁻⁴ years⁻¹*28650 years + Ln[1]
Ln[A] = -3.4657
[A] = 0.0313 =
3.1% is the fraction of the sample after 28650 years