00:01
Okay, so we know in this problem that k -alpha x -ray was emitted with an energy, let's put here, an energy k -alpha, sorry, energy k -alpha of 7 .46 kev.
00:26
And we must discover from which sample of element this k -alpha x -ray was emitted.
00:40
So first of all, we must remember that in the x -ray spectrum, the k -shell has two spikes.
00:56
Therefore, if we remember about the formula, the equation for energy, so energy of k -alpha, will be something like z square that multiplies 10 .2 electron volts.
01:16
Okay, but there is a problem since for this element, actually for all elements, the k -shell has two spikes, we must just consider one of them.
01:29
So the correct equation will be z minus 1 square.
01:37
Okay, therefore we want to solve this for z so then we can discover what element this is this.
01:47
So this equation can be found in equation 41, 48 of the textbook for reference.
01:57
So let's solve this equation for z...