00:01
In this question, we have three negative charges arranged in a vertical line.
00:06
We want to find an electric field at point p.
00:12
So to solve this problem, we need to remember that electric fuel is a vector.
00:22
So when we want to find a net electric field, we need to do a vector sum.
00:27
And then for point charges, electric fuel due to point charges.
00:32
Charge, okay, will be k, q divide by r square.
00:47
So first thing we need to do is to find a draw the electric fuel vectors at point p due to the three charges.
01:00
So we look like this.
01:04
So for negative charges, electric few vectors will point toward the charge.
01:09
So we have e2 pointing into the.
01:12
Left we have e1 pointing up and e3 pointing down.
01:30
And then these angles are the same, okay, because they are equidistant from point p.
01:39
So, and we also need to find out the distance.
01:43
So we know the distance r2, which is 6m, the distance between q1 and p.
01:50
So just note that we have a 6, 8, 10 triangle.
01:56
So this is 10 cm using pythagoras theorem...