Answer:
Explanation:
half life of radium-224 = 3.6 days
1 half life = 3.6 days
2 half lives = 7.2 days
3 half lives = 10.8 days
No = 36 g
Nt = sample remaining
Nt = No(1/2)^t/t1/2
After 1 half-life:
Nt = 36(1/2)^3.6/3.6 = 36(1/2)¹ = 18 g
After 2 half-live:
Nt = 36(1/2)^7.2/3.6 = 36(1/2)² = 9 g
After 3 half-life:
Nt = 36(1/2)^10.8/3.6) = 36(1/2)³ = 4.5 g