Calculation of true thickness of the bed

 

28) The Void ratio (in percentage) of sandstone is 25. Its porosity in percentage is

(Thanks to Chandrasekhar, ANU)

Solution:

 Given that the void ratio (e) = 25 % = 0.25

 Porosity ($\phi$) = ?

 We know the relation between the void ratio and the porosity as

 $porosity (\phi)=\frac{void ratio(e)}{1+ void ratio(e)}$

$\phi= \frac{e}{1+e}$

$\phi= \frac{0.25}{1+0.25}$

$\phi= \frac{0.25}{1.25}$

$\phi= 0.2$

$\phi$ = 20%