00:01
And in this question, you look at the decay of some radioactive element, which in this case is radon, right? so this element has a half life, which is t half, which is a generate half, which is 1 .6 times 10 to 3 years, right? so that's 1 ,600 years.
00:21
Now, if the sample initially contains how much nuclear, and nought equals 3 .9 times 10 to 6.
00:30
16, right? initially you have so much nuclei, right? and what is the initial activity in curis, right? the initial activity in curis is simply given by l0 times, you know, divided by the decay rate, which is given by the inverse of the decay lifetime, which is related to the half -life by this simple equation, noclerism of two, right? so from this half -life, you work out the decay rate, you work out the decay lifetime and take the inverse, multiplied by the initial number of nuclear, then you get the initial activity.
01:07
If you want to express in q rate, then what you need to do is divide this by 3 .7 times 10 to 4, right? that's per second, right? that's the one macron q rate.
01:27
So just divide this by the, you will get the turing.
01:32
The number of radium nucleic remain after so many years.
01:37
Well, that is just n -t, how many years? i think it's 4 .7 times, it's just 4 ,700 years.
01:47
And obviously, what you need, what you would get is just n0 times e minus t over t, right? so t is just this.
01:56
Plucking the numbers, you will get the answer...