Question

Water flows from P to Q through two soil samples, Soil 1 and Soil 2, having cross sectional area of 80$c{m}^2$ as shown in the figure. Over a period of 15 minutes, 200 ml of water was observed to pass through any cross section. The flow conditions can be assumed to be steady state. If the coefficient of permeability of soil 1 is 0.02 mm/s, the coefficient of permeability of Soil 2 (expressed in mm/s) would be

• A. 0.0454

Answer 1

The correct option is A 0.0454
q = $k_i{I}_{i}A$

$\frac{200\times {10}^{-6}}{15\times 60\times 80\times {10}^{-4}}=k_1\times \frac{h_1}{l_1}\therefore h_1=\frac{5}{24}m$

$l_1=0.15m$

Now,

$K_1{h}_1=K_2{h}_{2}and{h}_1+h_2=0.3$

$K_2=\frac{K_1{h}_1}{h_2}$ $\therefore h_2=\frac{11}{120}$

$K_2=0.0454mm/sec$