00:01
Hello students in this question we have to determine the equivalent resistance of the ladder which is given and the value of each resistance is 175 oms and in the b part we have to find the current through each of the three resistors on the left if a 50 -volt battery is connected between points a and b so let's see the diagram first so here this is a ladder so in the a part we have three resistors in series here so when three resistance are in series so they add up so r plus r plus r is 3 r now this r1 will be parallel with the this this r so this will be suppose r 2 so r2 will be r1 multiplied by r over r1 plus r so here the value of r1 is 3 r multiplied by r multiple by r will be 3 r square over this will be 3 r plus r so this will be 3 r plus r so this will be 3 over 3 over 4 r so this will be 3 over 4 r so r2 will be now r2 will be in series with this r and this r.
01:08
So that is suppose r3.
01:10
So it will be r plus r2 plus r.
01:15
So it is r plus 3 over 4r plus r.
01:21
So if we take 4 lcm, so 4r plus 3r plus 4r plus 4r.
01:27
So this is 4 plus 4 8 plus 3 is 11 over 4.
01:32
R this is r3 this is 11 over 4 r now this 11 over 4 r is in parallel with this r r 4 will be equal to r3 multiplied by r over r3 plus r so r3 is 11 over 4 r square over this is 11 over 4 r plus r so here we have 11 over 4 r square over we have 4 lcm so 11 r plus 4 r so this is 11 r square over 4 multiplied 4 over 15 r so 4 and 4 are cancelled so we have 11 over 15 r so now this r 4 is in parallel with this r and this r so are effective will be r plus r 4 plus r so it will be here r plus 11 over 15 r plus r so we take 15 and then so this is 15 r plus 11 r plus 15 15 is 30 plus 11 is 41 over 15 r this is the effective resistance now we put the value of r so are effective is equal to 41 over 15 so, r effective will be equal to, so here r comes out to be 477 .75 oms.
03:16
Now in the b part, it has been asked that the current through the three resistors on the left when a battery of 50 volt is connected across a and b.
03:26
So we have to find the current through these three registers.
03:30
So first of all, we find the total current that is passed, that is coming out of the battery.
03:35
So we know that here v is equal to i r.
03:40
So current i will be v over r.
03:43
So the total current will be 50 over the effective resistance that is 477 .75.
03:51
So here the value of i comes out to be 0 .105 amperes...