00:01
So we're going to apply the loop rule and we're going to do it to this upper loop going from a, k -l -e, d -c -b, and back to a.
00:11
So first we're going to start by going from a to k.
00:15
And when we go between these two points, we're crossing a voltage source and we're doing it from the negative to the positive side.
00:23
So that's going to be an addition of voltage.
00:26
So we're going to write e2 there.
00:28
And from k to l, we're going across a resistor and we're doing it in the same direction as the current is drawn, this current i2.
00:37
So that's going to be a subtraction of voltage.
00:40
So we have i2 times r2.
00:44
And then going from l to e, again, there's another resistor, and it's the same current, same direction.
00:51
So we can write minus i2 times big r2...