To calculate how much of the radioactive element X remains after 10 days, we can use the concept of half-lives.
The half-life of element X is 5 days. After each half-life, half of the remaining substance is gone.
After 5 days (1 half-life):
- Starting with 100 grams, after 1 half-life (5 days), you have: \[ 100 \text{ g} \div 2 = 50 \text{ g} \]
After another 5 days (2 half-lives, totaling 10 days):
- From the 50 grams remaining after the first half-life, after another half-life (the second half-life), you have: \[ 50 \text{ g} \div 2 = 25 \text{ g} \]
So, after 10 days, 25 grams of element X remains.
The answer is (a) 25 g.
1 answer