Falling head permeability test is carried out on a soil specimen having
cross-sectional area of 60 sq.cm. and height of 15 cm. The water level in the stand
pipe of diametre of 0.5 cm drops from 100 cm to 40 cm in half an hour. What is the coefficient of
permeability (cm/s)?

A

$$2.49\times10^{-5}$$

B

$$2.50\times10^{-3}$$

C

$$3.38\times10^{-4}$$

D

$$5.09\times10^{-5}$$