00:01
We are considering the circuit that is shown with resistances and emfs that are given.
00:09
And we want to figure out what is the voltage difference between points d and c.
00:18
And the voltage difference across, sorry, between points d and c is just going to be equal to the voltage drop across resistors.
00:31
Which is going to be given by current i2 times resistor r2 by oms law.
00:40
So in order to figure out and answer this question, we need to figure out what the current i2 is so that we can then use that to figure out the voltage.
00:53
So in order to do this, we need to use kirkhoff's laws and write some expressions for the loops.
01:02
So for the right side loop, i'm going to make a circle and we end up with emf2 plus i2r2 plus i3r3 is equal to zero.
01:25
For the left hand loop, we end up with minus i3r3 plus i1.
01:35
R1 minus emf1 is equal to 0.
01:41
For the big loop, because i may as well write everything out now, we end up with minus emf1 plus emf2, plus i2r2 plus i1r1 equals 0.
01:59
And using the junction rule, we get that current i2 i'm using the junction rule at point d current i2 is equal to i1 plus i3 so we have plenty of equations here to be able to solve for what we need um and so it's going to just be a lot of algebra from here on out the first thing that i did to solve was to plug in the current into the left hand loop...