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 = V_{v}/V_{s}

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.