The half life of the radio active substance is the time require the half the substance to decay. the mount A ( in grams) of 100 gram sample of a radio active substance remaining after t half lives by A equals to 100 (0.5) t. suppose the substance has a half life of 10 days. explain how to find the amount left after 40 days. than find the amount..
No
100 (0.5)^t
It is to the power of number of periods like compound interest
40 days is 4 half lives
so
100 (0.5)^4
= 100/16
To find the amount left after 40 days for a substance with a half-life of 10 days, you can follow these steps:
1. Determine the number of half-lives that have passed: Since the half-life is 10 days, divide the given time (40 days) by the half-life: 40 days / 10 days = 4 half-lives.
2. Use the formula A = 100 (0.5) t, where A is the amount remaining after t half-lives. Plug in the values: A = 100 (0.5) 4.
3. Calculate the amount remaining: A = 100 (0.5)^4 = 100 (0.0625) = 6.25 grams.
Therefore, the amount left after 40 days is 6.25 grams.
Note: The formula A = 100 (0.5) t assumes that you start with 100 grams of the substance. If the initial amount is different, you need to modify the formula accordingly.