00:01
And this problem we're thinking about charges in magnetic fields.
00:06
And the first question asks us how will an electron and a proton be active upon differently in a magnetic field? the main difference is that protons are more massive and they have opposite charges.
00:33
So the fact that protons are more massive means that for the same force, which they'll experience the same magnitude of force because they have the same magnitude of charge and the magnitude of the magnetic field is the same.
00:55
The more massive object will experience the smaller acceleration because of mutant second law.
01:01
So protons are more massive, which means the electron accelerates more.
01:16
It has a larger acceleration.
01:18
And they have opposite charges, which means they will move in opposite directions.
01:35
For the problem, we're told, i believe it's a proton that's moving with a speed of 1 .14 times 10 to the 5th meters per second.
01:49
We're told the magnetic field has a value of 58 .5 micro tesla or 58 .5 times 10 to the negative 6 tesla.
02:05
And we want to know the direction of the magnetic field.
02:11
Based off of the description and the problem, we're told that when the particle moves northward, it feels no magnetic force.
02:21
And so that means that the magnetic field must either be directed northwards or southwards.
02:31
And so to figure out which direction it is, we need to also take into account what particle it is.
02:44
So we have a proton moving eastward.
02:50
For a proton moving eastward, if it interacts with a magnetic field directed north, the force will be directed upwards by the right -hand rule, and so that must mean that our magnetic field is north.
03:12
For part b, we want to find the magnitude of the force.
03:18
So the magnetic force is equal to qvb, sign of theta.
03:27
We know that they're moving at right angles to each other.
03:30
So sign of theta is going to be equal to one...