00:01
For this question, we want to find the kinetic energy of the beta particle of this decay, where potassium actually decays via beta minus, right? beta minus, where it is actually an electron.
00:24
And what we get is we get a neutrinal, antineutrino, as well as calcium, right? because the proton number has changed.
00:40
And so to get the energy that was imparted into the beta particle, we would need to find what is the energy being released from this decay reaction.
00:58
And to get the energy that was released, we are simply looking at binding energy, right? so the binary energy we can get by looking at the mass difference multiplied by c squared.
01:14
So the mass difference, we are looking at mass difference between the calcium, as well as the calcium plus the beta particle, subtracted by the potassium nucleic.
01:29
So we can start with the calcium mass first, which is 39.
01:38
0 .962591 u.
01:46
This is for a calcium atom, so we gotta subtract away the electrons, right? so there's 20 electrons.
01:59
Then we add a beta particle, which is also an electron, right? so actually it's subtracting 19 electrons, but for clarity i'll just write it over here.
02:15
So this is for the right hand side of the equation.
02:21
Subtracted by the mass of the potassium nucleate.
02:27
So the potassium nucleate, the mass is actually 39 .963 -998 -7 u...