Answer:
85.5 minutes
Step-by-step explanation:
The amount of an element that will remain after time t can be expressed as a function of initial amount N0, time t, and half life th as;
Nt = N0 × e^(-λt)
Where;
Decay constant λ = ln(2)/th, substituting into the equation;
Nt = N0 × e^(-ln(2)t/th)
We need to make t the subject of formula;
Nt/N0 = e^(-ln(2)t/th)
ln(Nt/N0) = -ln(2)t/th
t = ln(Nt/N0) ÷ -ln(2)/th
Given;
Initial amount N0 = 760g
Final amount Nt = 11 g
Half life th = 14 minutes
the nearest tenth of a minute, would it take the element to decay to 11 grams can be derived using the formula;
t = ln(Nt/N0) ÷ -ln(2)/th
Substituting the given values;
t = ln(11/760) ÷ -ln(2)/14
t = 85.5 minutes
