How long will a radioactive isotope, whose half-life is T years, take for its activity to reduce to 1 8 th of its initial value?

Step-by-step solution

After n half lives, activity, A = A 0 ( 1 2 ) n given that A = A 0 8 A 0 8 = A 0 ( 1 2 ) n n = 3 ∴ time = 3 T