00:01
Hi, in the given problem there is a combination.
00:04
A multi -loop circuit.
00:08
The first loop is having a resistance r1 is equal to 10 .0 om.
00:16
There is a battery providing a potential of v2 is equal to 9 .00 volt.
00:27
In this loop and one more resistor having a resistance of r2 is equal to 20 .0 om.
00:39
Then there is another loop having a resistor providing a resistance of r3 is equal to 30 .0 oom and a battery providing the potential of v1 is equal to 15 .0 volt and this is the complete circuit representing multiple loops now we can name the junctions a b c d e and f now the given currents in the circuit are here this is i1 moving towards right through r1.
01:25
Then there is a current i2 moving again towards right through r2.
01:33
And finally here this is i3 and interestingly that is also moving towards right through r3.
01:41
Now all these three currents are meeting here at the junction e, i1, i2, and i3.
01:55
So first of all, using kirchhoff's junction rule at the junction e we get i1 plus i 2 plus i 3 as all the three currents are entering into the junction but none of the current is leaving so is equal to 0 or we can say equation for i3 is equal to minus i1 plus i 2 we can mark it as equation number 1 now we will apply kirchhoff's voltage law or loop rule so first of all using kirchhoff's loop rule in closed loop a b e f f a, this upper loop, let it be loop first.
03:10
So in this loop if we apply kirchof's loop rule, first of all, it says the algebraic sum of potential drops.
03:19
So the potential will be dropping in this loop at two places.
03:24
First of all, this is i -1r -1 and that is clockwise.
03:29
So it will be taken as positive.
03:31
But for i -2 into r2 that will be taking place counterclockwise.
03:35
So it will be taken as negative and battery v2 is sending its current in counterclockwise direction again so it will also be taken as negative and this kirchop's loop rule says algebraic sum of potential drops means i1 r1 with positive is equal to sorry i 1 r1 positive minus i2 r2 negative is equal to minus v2 now plugging in the known values it becomes 10 i1 the r1 value of r1 is 10 oan 10 i1 minus 20 i 2 is equal to minus 9 so we can mark it as equation number 2 now the same rule kirchop's loop rule in loop closed loop b c d e b b and in this closed loop, the potential drop i3 into r3 counterclockwise.
04:44
The potential drop i2 into r2 here it will be clockwise.
04:49
Battery providing voltage v2 clockwise, battery providing voltage v1, clockwise.
04:56
So using the same kirchops loop here we get i2r2 minus i3r3.
05:09
Is equal to v2 plus v1 or we can say plugging in all the known values this is 20 i2 minus 30 for r3 and i 3 from equation number 1 this is minus i 1 plus i 2 is equal to 15 for v2 v1 is 9.
05:33
So, rearranging the terms we get here, 20 i2 plus 30 i1 plus 30 i2 is equal to 24 or we get it to be 30 i 1 plus 50 i 2 is equal to 24 which is a 20 i 1 plus 50 i 2 is equal to 24 which is equation number 3.
06:10
Now equation number 2 saves 10 i 1 minus 20 i 2 is equal to minus 9...