The dimensions of a block are 1 cm × 1 cm × 100 cm. If the specific resistance of its material is 3 × 10^-7 ohm m, then the resistance between the opposite rectangular faces is :

3 × 10^-7 ohm

$R = (\rho l/A)$

$\rho=3 \times 10^{-7} \mathrm{ohm}~\mathrm{m}, l=1 \mathrm{~cm}=10^{-2} \mathrm{~m} \text { and } \mathrm{A}=1 \times 100 \mathrm{~cm}^2=10^{-2} \mathrm{~m}^2$

∴ $\mathrm{R}=3 \times 10^{-7} \times \frac{10^{-2}}{10^{-2}}=3 \times 10^{-7} \mathrm{ohm}$