Two electrolytic solutions of substances $A$ and $B$ have $0.1 \mathrm{M}$ concentration and respective specific conductances, $4.7 x {10}^{- 4}$ and $3.5 x {10}^{- 2}$ ${\text{ ohm }}^{-}{\mathrm{cm}}^{-}$ Which of these offers more resistance for the flow of current and which one is a stronger electrolyte ? 

We know that:

Specific resistance, $\mathrm{\rho }=\frac{1}{\text{ Specific conductance }\left(\mathrm{K}\right)}$

For substance A : $\mathrm{\rho }=\frac{1}{\mathrm{K}}$

                            $=\frac{1}{4.7\times {10}^{-4}{\mathrm{ohm}}^{-}{\mathrm{cm}}^{-}}$

                                    $=2127.66 \mathrm{ohm} \mathrm{cm}$

For substance B: $\mathrm{\rho }=\frac{1}{\mathrm{K}}$

                               $\begin{array}{r}=\frac{1}{3.5\times {10}^{-2}{\mathrm{ohm}}^{-}{\mathrm{cm}}^{-}}\\ =28.57 \mathrm{ohm} \mathrm{cm}\end{array}$

Since the substance A offers more resistance $(2127.66 \mathrm{ohm} \mathrm{cm})$than $\mathrm{B},$ it is a weaker electrolyte and has less conductance. So, B is a stronger electrolyte.