After 76 seconds, half of the radium-222 would have decayed (its half-life is about 3.8 days). Therefore, the quantity of radium-222 remaining in the 12-gram sample would be 6 grams.
After 1.6 seconds, 0.6 g astatine-218 remains unchanged. This amount is reduced by half to 0.3 g at 3.2 seconds. It is halved again at 4.8 seconds to 0.15 g, and halved once more to 0.075 g unchanged after a total of 6.4 seconds.
reference table N: Half Life of Rn-222 is 3.823d = 8/3.823 = # of Half lives = 2.09 (roughly 2) 20g-> 40g-> 80g doesn't say anything about decay so assume to increase since how much will remain in 8days Ans: 80g
One sixteenth of a gram. 1st halflife- 1/2 gram 2nd, 1/4 3rd 1/8th 4th halflife, 1/16th
10 grams... If the half-life is 100 years, that means after 100 years, half the original mass remains. After another 100 years, the mass is halved again. 40/2=20... 20/2=10.
If a sample of radioactive material has a half-life of one week the original sample will have 50 percent of the original left at the end of the second week. The third week would be 25 percent of the sample. The fourth week would be 12.5 percent of the original sample.
The answer depends on 3240 WHAT: seconds, days, years?
To determine the remaining amount of a 200 gram sample after 36 seconds with a half-life of 12 seconds, we first calculate how many half-lives fit into 36 seconds. There are three half-lives in 36 seconds (36 ÷ 12 = 3). Each half-life reduces the sample by half: after the first half-life, 100 grams remain; after the second, 50 grams; and after the third, 25 grams. Therefore, 25 grams of the sample would remain after 36 seconds.
50 mg
Approx 1/8 will remain.
This would depend on the specific sample and its stability. Without additional information, it is not possible to determine how much of the sample would remain unchanged after two hours.
To determine the percentage of As-81 that remains undecayed after 43.2 seconds, you would need to know its half-life. As-81 has a half-life of approximately 46.2 seconds. Using the formula for radioactive decay, after one half-life (46.2 seconds), 50% would remain. Since 43.2 seconds is slightly less than one half-life, a little more than 50% of the sample remains undecayed, but the exact percentage requires calculations based on the exponential decay formula.
1.5% remains after 43.2 seconds.
5g would remain
Substance in the material Remain the same
The half-life of 27Co60 is about 5.27 years. 15.8 years is 3 half-lives, so 0.53 or 0.125 of the original sample of 16 g will remain, that being 2 g.
Approximately 400 grams of the potassium-40 sample will remain after 3.91 years, as potassium-40 has a half-life of around 1.25 billion years. This means that half of the initial sample would have decayed by that time.
To determine the percent of As-81 that remains un-decayed after 43.3 seconds, you would need to know its half-life. The half-life of As-81 is approximately 46.2 seconds. Given that 43.3 seconds is slightly less than one half-life, you can use the formula for exponential decay: [ N(t) = N_0 \left( \frac{1}{2} \right)^{t/T_{1/2}} ] where ( N_0 ) is the initial quantity, ( t ) is the elapsed time, and ( T_{1/2} ) is the half-life. After 43.3 seconds, about 80% of the original sample of As-81 would remain un-decayed.