The correct answer is b) 2 half-lives.
In the given scenario, if 50% of the radioactive element remains after 4000 years, it means that each half-life of the element is 4000 years. Thus, in order for the remaining amount of the element to reach 50%, it would need to go through 2 half-lives, or a total of 8000 years (2 x 4000 years).
If 50% of a radioactive element remains after 4000 years, what is the half-life?
a
1 half-life
b
2 half-lives
c
3 half-lives
d
4 half-lives
3 answers
The half-life of a certain radioactive element is 1,250 years. What percent of the atoms remain 7,500 years?
a
6.25%
b
50%
c
25%
d
1.5625%
a
6.25%
b
50%
c
25%
d
1.5625%
The correct answer is d) 1.5625%.
To calculate the percent of atoms that remain after a certain time, we can use the formula:
Percent remaining = (1/2)^(t/h) * 100
where t is the time elapsed and h is the half-life.
In this case, we have t = 7500 years and h = 1250 years.
Plugging these values into the formula, we get:
Percent remaining = (1/2)^(7500/1250) * 100
= (1/2)^6 * 100
= (1/64) * 100
= 1.5625%
Therefore, approximately 1.5625% of the atoms remain after 7,500 years.
To calculate the percent of atoms that remain after a certain time, we can use the formula:
Percent remaining = (1/2)^(t/h) * 100
where t is the time elapsed and h is the half-life.
In this case, we have t = 7500 years and h = 1250 years.
Plugging these values into the formula, we get:
Percent remaining = (1/2)^(7500/1250) * 100
= (1/2)^6 * 100
= (1/64) * 100
= 1.5625%
Therefore, approximately 1.5625% of the atoms remain after 7,500 years.
1 answer