A falling head permeability test was carried out on a 15 cm long sample of silty clay. The diameter of the sample and the standpipe were 9.8 cm and 0.75 cm, respectively. The water level in the standpipe was observed to fall from 60 cm to 45 cm in 12 minutes.
Calculate: a. The hydraulic conductivity k of the soil sample .
b. Height of water level in the stand pipe after another 20 minutes.
c. Time required for the water level to drop to 10 cm