In the figure, the value of resistors to be connected between `C` and `D` so that the resistance of the entire circuit between `A` and `B` does not change with the number of elementary set used is

Options

A. `R`
B. `R(sqrt(3)-1)`
C. `3R`
D. `R(sqrt(3)+1)`

Answer

B

Explanation

Resistance between AB is independent of number of sets used Let x be the `R_(eff)` between AB
`A=R||[2R+(Rr)/(R+r)]` .(i)
`x=R||[2R+x]` …(ii)