find eqv resistance... classic prob

find equivalent resistance across AB (the two points at the base of the outermost equilatral trianngle..)

hint: use principle of symmetry.

12 Answers

1
greatvishal swami ·

s0

(x/2.R/x/2+R+R)||(R)=x

where || means 'is in parallel with'
** assuming
1. that RAB=RBC=RCA=R
2. x is the net resistance of circuit

11
Anirudh Narayanan ·

What's the principle of symmetry? [7]

1
Akshay Pamnani ·

Is the answer R/2??

62
Lokesh Verma ·

Sky.. this question has 2 variations...
1) Each resistance is R
2) The resistance is proportional to the length of the wire!

1
Akshay Pamnani ·

I considered every line to be a resistance R

1
skygirl ·

every line is R.

1
skygirl ·

dun u guys think the points T1, T2 , T3 are equipotential points.. //

1
dimensions (dimentime) ·

arey every line is R means every sides of triangle has R or what ???

i mean, res of AB is R or resistance of AC is R where C is point of intersection of vertex 2nd largest triangle with AB ?????????

1
skygirl ·

yes the ans is R/2 :) ... [if u take each section as R]

1
skygirl ·

@dimen... ,, its not mentioned in the question clearly...

1
Akshay Pamnani ·

It is a symmetry question
the circuit is symmetrical about the perpendicular line to AB so all the junctions can be removed along perpendicular,and now from A to mid point and C to mid point same potential drop,so inner network useless,now four resistances each of R/2 left,with equivalent R/2

1
skygirl ·

well done :)

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