00:01
Okay, we're looking at question 28 .42.
00:04
We have a long solenoid and we're given the magnetic field that we want for the center of the solenoid and we're asked to find the current.
00:12
So over here on the left, i've listed the information that we have.
00:17
We're given that we want the magnetic field, the number of turns, the length of the selenoid, and i've converted the length into meters.
00:25
The diameter also converted to meters of course our mu not we always will need to know and we're again trying to solve for the current here so to do this we want the formula for the magnetic field of a solenoid at the center of the solenoid and that's mu not times little n times i and remember our little n is going to be the number of turns per unit ranks so to calculate that we do the total number of turns n divided by few length l.
01:01
So luckily we have both capital n and l, so we're going to be able to determine n.
01:07
Now if we plug that into our formula here, just put that in like this for us.
01:15
Remember we want to solve for i.
01:17
So before we plug in numbers, why don't we just rearrange this equation to give us i? so to do that, we're just going to do that, we're just going to to divide both sides by mu not and then multiply each side by l over n...