9its definitely not easy
kindy change ur topic!!!!
ans obtained by grounds of symmetry
Identical wires, each with resistance R, are connected so as to form the edges of the platonic solid Icosahedron.(The figure is given , additionally note that it is a polyhedron with 20 faces, each face an equilateral triangle).Determine the resistance of the network between the two opposite vertices A and B.
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1try it celestine then you will get to know that it is indeed easy
1this is a olympiad q
i asked ma sir last year he tld meh 2 apply loop laws n solve :(
9ppl try this its got a very elegant sol
its an inpho 1999 prob but of jee level only
33Yup celestine. very elegant indeed.
But,How you know from where the question is?
1my ans may be right but i'm not sure whether the method is right, pls correct me if i'm wrong
assume A and B connected externally thru a battery.
by symmetry equal current flows in all the branches(indicated by arrow), so the potential drop across each of those resistors is the same.
so the resistors marked in red can be removed and its ends shorted.
continuining... this way u get
Reff=R/5 + R/10 + R/5 = R/2