125
At 8.1 days, 400 atoms of Au198 would remain in the sample. This is because after 8.1 days, two half-lives of Au198 have passed, reducing the initial 800 atoms to 400.
Based on the half-life of Na-24, after 1 half-life (15 hours), there would be 500 atoms remaining. After 2 half-lives (30 hours), there would be 250 atoms remaining. After 3 half-lives (45 hours), there would be 125 atoms remaining in the sample.
The top of a urine test bottle that starts with "L" is likely the lid, which is the cover that seals the bottle to prevent leakage or contamination of the urine sample.
Atomic decay is a random phenomenon whose distribution is exponential (generally). Thus if the average lifetime is t0 and you wait a time t, the probability that a single atom decay is p=(1-exp(-t/t0)) Thus if you have N atoms, the average number of atoms that decay in the tine t is <N> = N0 (1-exp(-t/t0)) where N0 is the initial number. naturally in a specific experiment the real number of atoms that decay in a time t will not be exactly <N>, this is only the average number over a potentially infinite number of experiments. However, greater N0, more likely the number of atoms observed in a specific experiment will be near to <N>. In your case <N>=188.1 and the expected deviation is of the order of 13, thus the result could fluctuates with high probability between 200 (that is all decay) and 162 (2 sigma point).
The half-life is 5730. This is because the half-life is the amount of time it takes for half of a sample to decay. In this case, the sample is 100 atoms, and half of 100 is 50, so the amount of time it takes the sample to reach 50 atoms is it's half life...5730!
At 8.1 days, 400 atoms of Au198 would remain in the sample. This is because after 8.1 days, two half-lives of Au198 have passed, reducing the initial 800 atoms to 400.
Based on the half-life of Na-24, after 1 half-life (15 hours), there would be 500 atoms remaining. After 2 half-lives (30 hours), there would be 250 atoms remaining. After 3 half-lives (45 hours), there would be 125 atoms remaining in the sample.
At 2.7 days, half of the 800 atoms (400 atoms) would have decayed. At 8.1 days, three half-lives have passed, so only ( \frac{1}{2} \times \frac{1}{2} \times \frac{1}{2} = \frac{1}{8} ) of the original sample remains. Therefore, there are 100 atoms of Au-198 remaining in the sample after 8.1 days.
After 8.1 days, three half-lives have passed (8.1 days / 2.7 days = 3). With each half-life, the number of atoms is halved. Therefore, starting with 800 atoms, after three half-lives there would be 800 / 2 / 2 / 2 = 100 atoms remaining.
There is no upper limit; when the stopwatch reaches the largest number of seconds it can count, it simply starts over. It is your job to count the number of times it starts over. Most digital stopwatches can time up to 20 hours, resetting after 19:59:59.99.
Kraft scientist
· Marie Curie
archaeologist
To make a mechanical stopwatch, you’ll need gears, a spring, and an escapement that ticks evenly. The spring powers the gear train, the escapement keeps time steady, and a button starts and stops the movement. Adjust for smooth operation.
Albert Einstein
700 milliion years. The definition of half-life is the period of time during which one-half of the atoms of an element undergo decay into other elements.
Nils Bohr