00:01
In this question, we have a charge which has a uniform volume density equal to 1 .2 nanocolon per meter cubed, as indicated here by row.
00:11
We know that it fills an infinite slab between the x coordinates minus 5 and plus 5.
00:18
What we want to find is the magnitude of the electric field at a point with the coordinate x equals 4 and at any point with the coordinate x equals 6 centimetres.
00:27
So what we know is that at x is 0 .04 meters, the net field acts rightward from the charge lying between minus 0 .5 and 0 .04 and leftward on the other side, so in the region from 0 .04 to 0 .05 meters.
00:46
We know that sigma, so the total charge, is equal to the total enclosed charge, over the area, as stated by gauss's law, where this is the charge density.
01:05
We also know that this is equal to row times the volume over a, which is also equal to row delta x in the case of this question.
01:20
So what we can do is we can say that the net electric field, indicated by the modulus to say that it's the magnitude, is equal to the contribution on the left side, subtracting the contribution on the right side.
01:39
So, row 0 .09 meters over 2 epsilon 0, minus, because this part of the force is acting in the opposite direction, row 0 .01 over 2 epsilon naught, where this is the distance between minus 0 .05 and the position of where we're trying to find out the field.
02:10
So this is a difference of 0 .09 meters...