00:01
So this question asks us about a subatomic particle with a very short lifetime.
00:10
And so therefore the lifetime can't be measured, but we've measured the uncertainty in its energy to be 10 mep.
00:18
And so what we can use here is the energy time uncertainty principle first discovered and expanded on by heisenberg, which says that the uncertainty in energy multiplied by the uncertainty in time needs to be greater than or equal to h planck's constant over 4 pi.
00:42
And so the point here is that if we know, so we know delta e equals 10 m .e.
00:57
And so therefore we can find, we can find delta t, our inseparable.
01:06
Uncertainty in time.
01:07
And that uncertainty in time is going to be our lifetime of the particle.
01:13
As anything smaller than the lifetime of the particle, we are uncertain whether it's decayed or not.
01:19
And so if we set this equality equal such that it's the minimum uncertainty, so that's the lifetime of the particle, meaning past that, we aren't sure whether or not the particle is there or not.
01:30
So we can say that delta e, delta t must equal h over 4 pi.
01:40
And here we want to use units that leave us with a time in seconds.
01:46
So we can use standard units...