Answer:
After 3 half lives 10 g of radio active material left.
Explanation:
Given data:
Total amount of radio active material = 80 g
Amount left after 3 half lives = ?
Solution:
At time zero = 80 g
At first half life = 80 g/2 = 40 g
At 2nd half life = 40 g/2 = 20 g
At 3rd half life = 20 g/2 = 10 g
Thus, after 3 half lives 10 g of radio active material left.
