00:02
All right, hi everyone.
00:03
This time the concept we're going to look at is the electric field due to a point charge.
00:09
All right.
00:10
And so we have a square.
00:12
So let's draw a square.
00:20
And we've got point charges at the lower corners.
00:24
And we want to know what the field is right at the middle of the square.
00:28
Okay.
00:29
So at each corner, we have seven microcoulioms.
00:33
So seven microcoules here.
00:37
And seven microculems there.
00:41
The whole side is 0 .3 .00 meters by 0 .30 meters.
00:47
It is a square.
00:50
All right.
00:51
So if we look at the distance, we'll just draw our square again, just draw diagonals.
01:03
So this is where we want to know the field.
01:05
This is where we have our charges.
01:07
So the distance we need is this distance r.
01:13
Same over here, that distance r.
01:15
But this cuts the side right in half.
01:20
So this is 0 .15 meters, and so is this one.
01:26
0 .15 meters, and so is this height here.
01:31
So r squared is 0 .15 meters squared plus 0 .15 meters squared plus 0 .15 meters squared.
01:40
So r squared ends up being 0 .045 meters squared.
01:47
Okay, we're going to need that.
01:51
All right.
01:52
And so both of the charges are positive, so they're going to make electric fields that point out away.
01:58
And so if we draw in the electric field, we'll draw another square, make our x.
02:14
And so at this point, the electric field, due to the, we'll just call it q1, it's 0 .7 microcolons.
02:26
Its electric field is going to be pointing this way.
02:29
And let me just do that a different color.
02:33
Okay, so that's going to be electric field due to q1.
02:38
And then we'll put q2 over here, where this is q2.
02:43
And we can put its electric field in green, i guess.
02:47
Okay, its electric field is going to go like this.
02:50
All right, so we'll draw that off to the side here...