00:01
So this is a question about a mass spectrometer with charge q.
00:06
Mass of the ion is m.
00:09
We have a voltage difference, a magnetic field, and a radius, and we're asked how do you calculate m, the mass of the ion? so one thing that i know is that 1ā2 mv squared.
00:32
Equals the charge times the change in voltage.
00:43
So this would tell us the speed of the ion that enters the mass spectrometer.
00:58
Then also equating magnetic force, which is qvb, to centripetal acceleration, which is m v squared over r, and putting this all together, we can solve for m.
01:23
So first of all, i'm going to solve the left equation for lowercase v for the speed.
01:36
And so v is the square root of 2q delta v over m.
02:01
Okay, now i'm going to solve this one for m...