00:01
In this problem on the topic of electric fields, we have three point charges that are aligned along the x -axis, as we can see in the figure.
00:08
We want to find the result of the electric field at the position 2 -0, and then at the position 0 -2.
00:16
Now, the field e1, due to the 4 nanoculum charge, is in the minus x direction.
00:26
And so, e1 is equal to the electric constant k -e times the magnitude of the charge cube.
00:35
Times the distance to the point in question r squared along direction r hat.
00:44
And so this is equal to 8 .99 times 10 to the 9 newton meter squared per coulom squared multiplied by the charge minus 4 times 10 to the minus 9 quoloms divided by its distance, which is 2 .5 meters squared and this is in the i -hat direction.
01:21
And so this gives us minus 5 .75 i -hat newton's a coulom.
01:33
And so likewise we can find the field e2 and e3 due to the 5 nanoculum and 3 charges respectively.
01:43
And so e2 is equal to, again, k .e times q over r squared, r hat, which is 8 .99 times 10 to the 9, newton meter squared per coulomb squared times the charge of 5 nanocoloms of 5 times 10 to the minus 9 couloms, all divided by 2 meters, squared and that's in the i -hat direction this gives us e2 to be 11 .2 newtons per coulom along direction i -hat and for the third charge we have the electric field e3 is again equal to 8 .99 times 10 to the 9 newton meter squared per koolom squared times a charge of 3 times 10 to the minus 9 couloms divided by a distance of 1 .2 meters squared and this as well is a long unit vector i hat this gives us e3 to be 18 .7 newtons per kulum i hat and so therefore the net electric field at the point to 0, we'll call it er, the resultant electric field is e1 plus e2 plus e3.
03:45
And all of these are in the same direction, so we can simply add the magnitudes, and that is 24 .2 neutrons per kulum in the positive.
04:00
X direction.
04:06
And so that's the resultant field at two zero...