Question

Strontium-90 has a half-life of 28.1 years. How many years will it take for a sample of Strontium-90 to decay to 25% of its initial quantity?

Answer 1

B

Explanation:

One half life there will be 50 %

another half life and there will be 25 %

so TWO half lives * 28.1 yrs/ half life = 56.2 yrs