16th_November_2008

Find the effective Resistance between A and B in the given circuit!

22 Answers

33
Abhishek Priyam ·

[1]

1
challenger ·

not getting that rohan's answer

1
challenger ·

then i got the same old answer

62
Lokesh Verma ·

Yes i did.. so there was a small trick.. find R' using the method first..

and then again use it in the circuti to find the equivalent resistance across AB! :)

1
challenger ·

62
Lokesh Verma ·

R'= (R+R'+2R)*2R
(R+R'+2R)+2R

above is wrong..
i have edited suitably below

R'= (R+R'+R)*R
(R+R'+R)+R

1
challenger ·

62
Lokesh Verma ·

dear i am sorry i catn get ur mind..

can u mail me the image at nishantsah at targetiit.com

i will check the image..

sorry for troubling u

1
challenger ·

I am unable to get the picture .but let me try explaining .let R effective be R' 2R ,2R in series with R'(assuming the infinite sequence as R')this in parallel with R.that gave me (2√2-2)*R

62
Lokesh Verma ·

gr8 work Rohan :)

Not as tough as this one looks :)

1
Rohan Ghosh ·

i applied the same method

1
roopa m k iyengar ·

heyy is the ansr fr dis is " 0.79R"

62
Lokesh Verma ·

so we are reduced to this circuit.. where each of the small part has a resistance of 1 ohm!

so the new question now boils down to finding the resistance across AB of this circuit!

This is again not very tough.

we know the resistance of the points between B and the point above B.

that is a standard question which u must have seen so many so many times :)

basically u replace that here. by the effective resistance...

so u are reduced the square loop... with 4 resistances only.. i hope this question helped u guys :)

62
Lokesh Verma ·

In the above figure, .. there is a symmetry about the red line.. or about AB.. so what happens is that the same colored points on either side of the red line are equipotential.. if we apply a potential across AB..

so for this circuit, if we joined these points together, it will not change the equivalent resistance.

on joining them, we will get the lower equivalent of the above figure..

where each black line is of resistance 2ohms.. and the red line of 1 ohm...

each node has 2 wires between them .. each are in paralllel..

so we can reduce it to the figure below:

continued in the next post:.....

62
Lokesh Verma ·

No solutions?

1
roopa m k iyengar ·

hey is equivalent cirrcuit diagram like this........

62
Lokesh Verma ·

yes rohan .. right answer :)

good work

62
Lokesh Verma ·

dude.. let me check 1 sec.. i have an anser in another form.. but may be u are right :)

1
Rohan Ghosh ·

i the answer =>R* (√3+1)/(√3+2)

62
Lokesh Verma ·

No neither !

1
varun ·

Lol I am getting the ans 0 this time :P

1
varun ·

Is it 2R ?

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