00:01
So what's my general half -life formula? well, my output, where t could be in years, or in this case, in minutes, equals my initial amount times i'm decaying to half my substance every multiple of t hours, or t over h hours.
00:15
Okay, so what do i know about this? well, at the beginning, i had 352 grams, so i started with 352.
00:21
Okay, and after 90 minutes, the sample has decayed to 5 .5 grams.
00:25
So my output is 5 .5, and after 90 minutes.
00:29
First, i wanna find my half -life.
00:32
Okay, so i wanna get h by itself.
00:34
I'm multiplying everything by 352, so i'm gonna divide by 352 to both sides.
00:40
Okay, leave this as is.
00:42
Then what am i gonna do? well, i have an exponent.
00:46
I have a variable in my exponent, so how am i gonna get that down? well, the inverse of exponential is logarithmic...