00:01
We have two charges arranged on the y -axis.
00:04
They're a distance d apart, and they're symmetrically located.
00:09
We want to find out what the electric field is along the y -axis.
00:17
So my point p, i put up here at distance y.
00:27
Electric field looks like this.
00:28
So in the denominator, for instance, of the plus charge, it's y -minus d over 2 is our distance.
00:36
And for the negative charge, it's y plus d over 2.
00:47
So i can factor out a kqj and just write out those fractions like that.
01:07
And then i'm actually going to factor out a 1 over y squared like that.
01:15
All i did was just bring the y squared out of the parentheses and divide by it on inside.
01:23
So d over 2y is presumably very small.
01:29
We're told to think that...