0:00
Hi.
00:01
So in the first part of this question, we have to use norton sturham.
00:04
So norton sturham states that we can simplify any circuit, no matter how complicated, to a simple one that only contains a battery and a resistor.
00:15
So in the case of the circuit drawn in the question, we have to simplify it to contain just one resistor.
00:21
So let's quickly draw the actual circuit.
00:26
So i have a resistor there, r1, and another one here, r4.
00:32
We have here rl and r3 here and then we have another resistor r2 on the bottom.
00:46
Right.
00:46
So to try to simplify this, we observe that r4 and rl are in parallel.
00:52
So they can replace by a single resistor with a resistance r4 plus rl, which if we look at the question, this is 5 plus 20, so 25.
01:06
Then here, r3 and our equivalent resistor are linked in parallel.
01:13
So we can replace them by an equivalent resistor 1 over r, which is equal with 1 over r3 plus 1 over 25.
01:21
Now r3 has a value of 14, so this will be 1 over 14 plus 1 over 25.
01:28
And you can do the calculation to find this equivalent resistor r.
01:31
And then we will basically have three resistors in series.
01:35
So we will have r1, we will have our calculated equivalent resistor r, this one, and then we will have r2.
01:47
And these three resistors are linked to the battery, which has a voltage v.
01:52
So now the total resistance of the circuit will be simply r1 plus r2 plus the value that we calculated r.
02:02
Now that we know the total resistance, we can find the total current i that flows through the circuit.
02:09
I will be simply given by the voltage divided by the total resistance.
02:15
So now we know the current that flows through r1.
02:19
In other words, we also know the current that goes here into this node.
02:25
And this current splits into il, so the current that flows through rl and i3.
02:33
Current that flows through r3...