00:01
All right, now in this question, we have two current carrying wires.
00:03
I'm assuming one goes in the page, one goes out of the page in this configuration.
00:06
And we're asked to find the magnetic field at a midpoint between them, point p, and also a point 10 centimeters above.
00:15
So this is d equal to 10 centimeters.
00:19
And that is the same distance that we have here and we have here.
00:22
So these are both d as well.
00:25
So in order to answer this question, we first have to determine the direction of the magnetic field.
00:29
So if i take my right hand and i point my thumb in the direction of the current for the red wire, that means my thumb is going into the page.
00:36
If i then curl my fingers when they're underneath it, i'll find that i have my fingers pointing that way.
00:41
So that's going to be b1 there.
00:43
And then above, i'm going to have my fingers curled.
00:47
They're going to be pointing to the right.
00:48
So that's going to be b1 for that part.
00:50
And then if i do the same thing with my thumb pointing out for both wires, sorry, for the blue wire, i'm going to have b2 going in the same direction.
01:04
Sorry, i drew it the other way there.
01:06
It's going to be 2, b2 going in the same direction.
01:08
And then b2 up top is going to go to the left as well, but it's going to be considerably smaller.
01:14
And so for our point p here, my magnetic field at point p is going to be just the sum of those two.
01:21
It's going to be b1 plus b2, and they're both going to be going to the left.
01:25
I know that b from a wire is mu 0 times i of that wire over 2 pi times my distance away, which in this case is going to be d.
01:33
And that's going to be added together for these two.
01:36
So this would be d1 and d2.
01:38
But d1 and d2 are going to be the same...