The sides of rectangular block are 2cm, 3cm and 4 cm. The ratio of the maximum to minimum resistance between its parallel faces is

Resistance between parallel faces of length 3 cm and 2 cm, ${\mathrm{R}}_1=\frac{\rho \times 4}{6}=\frac{2\rho }{3}$

Resistance between parallel faces of length 3 cm and 4 cm, ${\mathrm{R}}_2=\frac{\rho \times 2}{12}=\frac{\rho }{6}$

Resistance between parallel faces of length 4 cm and 2 cm, ${\mathrm{R}}_3=\frac{\rho \times 3}{8}=\frac{3\rho }{8}$

Ratio of max to min resistances, $\frac{R_{max}}{R_{min}}=\frac{\raisebox{1ex}{$2$}\!\left/ \!\raisebox{-1ex}{$3$}\right.}{{\displaystyle \raisebox{1ex}{$1$}\!\left/ \!\raisebox{-1ex}{$6$}\right.}}=4$