00:01
This question, we are given a circuit having an internal resistance of 18 volt.
00:06
The internal resistance of an 18 volt cell is negligible.
00:10
So there is a battery of 18 volt and the value of r1, r2, sorry, the r1, r3 and r4 is given.
00:16
So we need to find a value of r2.
00:18
It's also given that an ideal volt meter reach 5 volt across r4.
00:22
Okay.
00:22
So if across r4 we are given the potential difference and its resistance is also given, don't you think then we can find a current so current through i4 will be voltage through i4 which is 5 over its resistance which is 500 so 1 over 100 is something which we are getting 1 over 100 is 0 .01 this is the current through i 4 and obviously r4 and r3 are in series so we can say that this current actually is 0 .01 okay now we got to find the value of r2 from here so uh all right, let's try to see.
01:00
Let's see what else can we do.
01:02
If this current was x and this current went as 0 .01, so this current will be x minus 0 .01, right? so we can apply the kvl in this particular loop.
01:14
So if we do that, we have plus 18 minus x times r1, minus x minus 0 .01 times r2 is equal to 0.
01:28
Value of r1 is given as is 400 so we get 18 minus 400 x minus x r2 plus 0 .01 r2 is equal to 0...