Correct Answer - Option 3 : (ii) and (iii)
Explanation
a) Porosity (n):
The porosity (n) of soil is defined as the ratio of the volume of voids to the total volume of soil.
\(η = \frac {V_v}V \times 100\%\)
Vv = Volume of voids
V = Total volume of soil
Range of porosity 0 < n < 100%
b) Air content (ac):
The air content of soil (ac) is defined as the ratio of the volume of air voids to the total volume of voids.
\(a_c = \frac {V_a}{V_v} \times 100\%\)
Va = volume of air voids
Vv = volume of voids
c) Water content (w):
It is also called moisture content. It is the ratio of the weight of water (Ww) to the weight of soil solids (Ws)
\(w = \frac {W_w}{W_s};\;w ≥ 0\)
Range of water content (w)
w ≥ 0
There is no upper Limit to water content
d) Void Ratio (e)
The ratio of the total volume of voids to the volume of solids is called the void ratio
e = Vv/Vs
e > 0
In general e > 0, i.e. There is no upper limit for the void ratio
Note:
Porosity is always less than 100% but the void ratio may be less than 1 or greater than or equal to 1.
The relation between void ratio and porosity of soil sample is given as:
\(n\; = \frac{e}{{1 + e}}\)
Where
n is porosity and e is a void ratio.
