Question

A 100g sample of a radioactive element has a half-life of 5 days, how many grams of radioactive material will remain after 15days? a) 100g b) 50g c) 25g d) 12.5g

Answer 1

option d is correct.....................

Answer 2

Answer: d)12.5g of the radioactive sample will be remaining after 15 days

Explanation:

100g of the radioactive sample will undergo disintegration for 15 days(3 half-lives)

$Radioactive\ sample\ (N_{0})=100g\\T_{1/2}=5days\\N=N_{0}/2^{T_{given/T_{half}}}\\N=100/2^{3}\\N=100/8=12.5g$

12.5g of element will remain after a span of 15 days