Answer: 2 years.
Explanation:
Half life is the amount of time taken by a radioactive material to decay to half of its original value.
Half life is represented by \(t_{\frac{1}{2}\)
\(t_{\frac{1}{2}=\frac{0.693}{\lambda}\)
\(\lambda\) = rate constant
As the initial amount of 100 grams is decaying to mass of 50 grams which is half of initial value, it will take 2 years for the decay.
