2 is your answer hope you get it right
Answer:
17.04%
Explanation:
Actual Value = 173.1
Measured Value = 143.6
Percent error is obtained using the equation;
Percent error = (Measured - Actual) / Actual ]* 100
Percent error = [ (143.6 - 173.1) / 173.1 ] * 100
The absolute value of (Measured - Actual) is taken,
Percent Error = [29.5 / 173.1 ] * 100
Percent Error = 0.1704 * 100 = 17.04%
For radioactive decay, we can relate current amount, initial amount, decay constant and time using:
N = No x exp(-λt)
Half-life = ln(2)/λ
λ = ln(2) / 5730
N/No = 80% = 0.8
0.8 = exp( -ln(2)/5730 x t)
t = 1844 years